Donald Trump is risking "millions" of lives by deploying an aircraft carrier strike group near the Korean peninsula, a congressman has warned.
Democrat Ted Lieu of California also claimed the "risk of harm to US troops" had "significantly increased" in the last two days, citing the naval deployment and missile strikes on Syria following the alleged chemical attack in Idlib province earlier this week.
The US Navy has sent the 100,000-ton USS Carl Vinson, along with its support ships, to the western Pacific as a show of force amid fears over North Korea's nuclear weapons and missile programmes.
This year North Korean officials, including dictator Kim Jong-un, have repeatedly indicated an intercontinental ballistic missile test or something similar could be imminent, possibly as soon as 15 April, the 105th birthday of North Korea's founding president and celebrated annually as "the Day of the Sun".
Since January the Carl Vinson, one of the US' so-called "super-carriers", has participated in numerous exercises with the Japan Maritime Self Defence Force and Republic of Korea Navy, various maritime security initiatives, and routine patrol operations in the South China Sea.
Mr Lieu, who is a colonel in the US Air Force reserves, said on Twitter: "Note to @POTUS: Unlike Syria, N. Korea has nukes & can rain down artillery on S. Korea. You mess up and millions can die on Korean Peninsula.
"In the last 48 hours, @realDonaldTrump significantly increased the risk of harm to US troops in Syria and South Korea.
"#TheScaryThingIs what happens if N. Korea does another missile test after this “show of force” by US? Does @realDonaldTrump strike N. Korea?"
In January Mr Lieu introduced a bill to the House that would prevent President Trump from making a "first-use" nuclear strike without congressional approval.
After the US bombed Syrian military targets earlier this week North Korea said the strike "proves our decision to strengthen our military power to stand against force with force was the right choice a million times over".
Last month the repressive state declared it was ready for war with the US.
Its foreign ministry said: "The nuclear force of [North Korea] is the treasured sword of justice and the most reliable war deterrence to defend the socialist motherland and the life of its people. We have the will and capability to fully respond to any war which the US wants.
"If the businessmen-turned-US-officials thought that they would frighten us, they would soon recognise that their method would not work."
In March, Rex Tillerson, US Secretary of State, said military action against North Korea was an "option on the table".
Mr Trump's highest-ranking foreign policy advisor said during a visit to South Korea he would bring an end to the policy of "strategic patience". Instead, the US will explore a range of military options, alongside diplomatic, security and economic measures.
However, when President Trump and Chinese President Xi Jinping met in Florida this week, Mr Trump pressed his counterpart to do more to curb North Korea's nuclear programme.
Increasing pressure on Beijing to rein in its reclusive neighbour forms the main thrust of a national security review completed by Mr Trump's aides in relation to North Korea.
The US' options include economic and military measures but lean more toward sanctions and urging China to do more. Although the option of pre-emptive military strikes on North Korea is not off the table, the review prioritises less-risky steps and de-emphasises direct military action.
Additional reporting by agencies
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies