Burkhard Lischka, who sits on the Bundestag’s intelligence oversight committee, said: “If it proves to be true that the American president passed on internal intelligence matters that would be highly worrying."
Noting that Mr Trump has access to “exclusive and highly sensitive information including in the area of combating terrorism” the Social Democratic Party (SDP) politician said that if the President “passes this information to other governments at will, then Trump becomes a security risk for the entire western world”.
Mr Lischka’s party is part of Germany’s governing coalition led by Angela Merkel’s conservatives.
The Chancellor visited the White House in March, where Mr Trump – already a hugely unpopular figure in Germany - appeared to refuse to shake her hand during an awkward joint press conference.
Counter-terror operations were among the issues discussed by the two leaders, with Germany standing as Nato and intelligence partner.
Having led Germany under three presidents, Ms Merkel has also negotiated extensively with Vladimir Putin, who is expected to meet Mr Trump for the first time at July’s G20 summit hosted by the German Chancellor in Hamburg.
Allegations that the President passed Russian officials classified intelligence on Isis threats relating to a widening laptop ban on passenger aircraft have threatened to damage the US’ relationship with allies.
The information reportedly shared in last week’s closed-door meeting with Russian foreign minister Sergey Lavrov and ambassador Sergey Kislyak is said to have been received under an intelligence sharing agreement with Israel.
The scandal comes days before Mr Trump visits the country on his first foreign trip, with the Israeli ambassador to the US, Ron Dermer, saying it has “full confidence in our intelligence sharing relationship with the United States”.
The claims have sparked condemnation by both Republicans and Democrats following a series of apparently contradictory statements from the White House and Mr Trump.
Hours after top officials claimed the original Washington Post report on disclosures was “false”, the President tweeted that he had the “absolute right” to share “facts pertaining to terrorism and airline flight safety” with Russia.
The information appears to be related to the basis for a ban imposed by the US and UK in March on laptops and tablets from being taken in hand luggage from 10 airports in Muslim-majority countries, which could be expanded to Europe.
Aides have maintained that no “inappropriate” information was shared but repeatedly failed to deny the intelligence passed on was classified.
HR McMaster, the national security adviser, claimed the real threat to national security was leakers ”releasing information to the press".
In an off-camera briefing, White House press secretary Sean Spicer repeatedly refused to comment on specific allegations but at one point appeared to confirm intelligence was passed on.
When a journalist asked whether the US had reached out to the ally that provided the information, he replied: “I'm not going to comment on specifically where it came from.”
He added: “My understanding is the President, of course, has classification authority…so the President can always discuss common threats or common issues with other heads of government or other government officials as he deems appropriate to tackle the threats our country faces.”
Before disclosing intelligence to another country, there would normally be an evaluation of costs and benefits, close consultation with American agencies and detailed consideration of how to mitigate risks.
The biggest names involved in the Trump-Russia investigation
The biggest names involved in the Trump-Russia investigation
1/11 Paul Manafort
Mr Manafort is a Republican strategist and former Trump campaign manager. He resigned from that post over questions about his extensive lobbying overseas, including in Ukraine where he represented pro-Russian interests.
2/11 Mike Flynn
Mr Flynn was named as Trump's national security adviser but was forced to resign from his post for inappropriate communication with Russian Ambassador to the US Sergey Kislyak. He had misrepresented a conversation he had with Mr Kislyak to Vice President Mike Pence, telling him wrongly that he had not discussed sanctions with the Russian.
3/11 Sergey Kislyak
Mr Kislyak, the Russian ambassador to the US, is at the centre of the web said to connect President Donald Trump's campaign with Russia.
4/11 Roger Stone
Mr Stone is a former Trump adviser who worked on the political campaigns of Richard Nixon, George HW Bush, and Ronald Reagan. Mr Stone claimed repeatedly in the final months of the campaign that he had backchannel communications with WikiLeaks founder Julian Assange and that he knew the group was going to dump damaging documents to the campaign of Democratic candidate Hillary Clinton - which did happen. Mr Stone also had contacts with the hacker Guccier 2.0 on Twitter, who claimed to have hacked the DNC and is linked to Russian intelligence services.
5/11 Jeff Sessions
The US attorney general was forced to recuse himself from the Trump-Russia investigation after it was learned that he had lied about meeting with Russian Ambassador to the US Sergey Kislyak.
6/11 Carter Page
Mr Page is a former advisor to the Trump campaign and has a background working as an investment banker at Merrill Lynch. Mr Page met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republican National Convention in Cleveland. Mr Page had invested in oil companies connected to Russia and had admitted that US Russia sanctions had hurt his bottom line.
7/11 Jeffrey "JD" Gorden
Mr Gordon met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republian National Convention to discuss how the US and Russia could work together to combat Islamist extremism should then-Republican presidential candidate Donald Trump win the election. The meeting came days before a massive leak of DNC emails that has been connected to Russia.
8/11 Jared Kushner
Mr Kushner is President Donald Trump's son-in-law and a key adviser to the White House. He met with a Russian banker appointed by Russian President Vladimir Putin in December. Mr Kushner has said he did so in his role as an adviser to Mr Trump while the bank says he did so as a private developer. Mr Kushner has also volunteered to testify in the Senate about his role helping to arrange meetings between Trump advisers and Russian Ambassador to the US Sergey Kislyak.
9/11 James Comey
Mr Comey was fired from his post as head of the FBI by President Donald Trump. The timing of Mr Comey's firing raised questions around whether or not the FBI's investigation into the Trump campaign may have played a role in the decision.
10/11 Preet Bharara
Mr Bahara refused, alongside 46 other US district attorney's across the country, to resign once President Donald Trump took office after previous assurances from Mr Trump that he would keep his job. Mr Bahara had been heading up several investigations including one into one of President Donald Trump's favorite cable television channels Fox News. Several investigations would lead back to that district, too, including those into Mr Trump's campaign ties to Russia, and Mr Trump's assertion that Trump Tower was wiretapped on orders from his predecessor.
11/11 Sally Yates
Ms Yates, a former Deputy Attorney General, was running the Justice Department while President Donald Trump's pick for attorney general awaited confirmation. Ms Yates was later fired by Mr Trump from her temporary post over her refusal to implement Mr Trump's first travel ban. She had also warned the White House about potential ties former National Security Adviser Michael Flynn to Russia after discovering those ties during the FBI's investigation into the Trump campaign's connections to Russia.
The US has several intelligence-sharing agreements with allies, including the Five Eyes programme with Britain, Canada, Australia and New Zealand.
The fact the information reportedly went to Russia during investigations into alleged links between Mr Trump’s campaign team and the Kremlin has generated alarm, as well as Moscow’s ties with Iran, China and the Syrian government.
John McCain, the Republican former presidential candidate and Senate Armed Services Committee chairman said the reports were ”deeply disturbing“.
He said the claims sent a “troubling signal” to American partners around the world, and that if the information was shared without an ally’s knowledge, other countries could be from sharing intelligence in the future.
“Regrettably, the time President Trump spent sharing sensitive information with the Russians was time he did not spend focusing on Russia’s aggressive behaviour, including its interference in American and European elections, its illegal invasion of Ukraine and annexation of Crimea, its other destabilising activities across Europe, and the slaughter of innocent civilians and targeting of hospitals in Syria,” Mr McCain added.
Steny Hoyer, one of the most senior Democrats in the House of Representatives, said Mr Trump’s presidency was “dangerous” and the claims were the latest example a White House riven by incompetence, chaos and conflicts of interest.
“I think there is an erosion of confidence among the American people and an erosion of confidence of the international community,” he added.
Mr Hoyer added that it was too early to consider impeachment proceedings against Mr Trump, but that “it is time for Republicans to say, 'enough’”.
Additional reporting by APReuse content