Syrian rebels waged fierce battles with regime troops in a town along the Iraqi border today, capturing a string of security posts and the local police headquarters despite heavy government shelling and bombing runs by warplanes, activists said.
The rebel advances in the town of al-Bukamal in the eastern oil-rich province of Deir el-Zour coincided with the departure from the Syrian capital of the last of the United Nations military observers after their mission headed by former UN secretary general Kofi Annan, meant to help end the bloodshed in Syria, failed.
The seemingly intractable conflict in Syria has defied all attempts at mediation. Human rights groups say more than 20,000 people have been killed since the uprising against president Bashar Assad began in March 2011, and in the past month the fighting has spread from the country's smaller towns and cities to regime strongholds of Damascus and Aleppo.
Mr Annan announced earlier this month that he will resign on August 31, and will be replaced by veteran diplomat Lakhdar Ibrahimi on September 1.
In Damascus, Syrian deputy foreign minister Faysal Mekdad denied rebel claims that a Japanese journalist who died in the northern city of Aleppo this week was killed by government troops.
"Any journalist who behaves in an irresponsible way should expect all these difficult possibilities," he said following a meeting with Babacare Gaye, the head of the outgoing UN mission.
Veteran Japanese war correspondent Mika Yamamoto was killed on Monday, becoming the first foreign journalist to die in Aleppo since clashes between rebels and regime forces erupted there almost a month ago.
Rebels have said she was killed by regime forces. Japan's foreign ministry said she was hit by gunfire while travelling with rebels from the Free Syrian Army.
Mr Mekdad said Ms Yamamoto was killed by "armed groups" to frame the Syrian army.
Fighting raged, meanwhile, in al-Bukamal, which is located across the border from the Iraqi town of Qaim. The border crossing has been in rebel hands since last month, but wresting control of al-Bukamal itself from regime troops would expand the opposition foothold along the frontier.
The opposition already controls a wide swath of territory along the border with Turkey in the north as well as pockets along the frontier with Jordan to the south and Lebanon to the west, which has proven key in ferrying people and material into and out of the country.
Rebels have been fighting troops for days in al-Bukamal, but early today took over several checkpoints, the main police station and the local command of the Political Security Directorate, one of Syria's powerful intelligence agencies, according to Rami Abdul-Rahman, who heads the Britain-based Syrian Observatory for Human Rights.
"There is an attempt to take full control of al-Bukamal," Abdul-Rahman said.
The Local Coordination Committees activist group said warplanes bombed al-Bukamal, but Abdul-Rahman said the jets were flying over the town and struck nearby areas, not the town itself.
Abu-Omar al-Deery, an activist in the provincial capital of Deir el-Zour, said by telephone that there are "fierce battles" in al-Bukamal and that "the Free Syrian Army is trying to liberate and clean the city".
There was no immediate word on casualties.
The main battlefronts over the past month have been in the capital, Damascus, as well as Aleppo, where regime forces have struggled to stamp out a rebel offensive that began last month and succeeded in capturing several neighbourhoods in the city of three million people.
In a report released today, the human rights group Amnesty International said artillery, mortar fire and airstrikes by government forces in Aleppo are killing mostly civilians, including children. It said air and artillery strikes against residential neighbourhoods are indiscriminate attacks that seriously endanger civilians.
Amnesty said that during a 10-day fact-finding visit to Aleppo city in the first half of August, Amnesty investigated some 30 attacks in which more than 80 civilians, who were not directly participating in hostilities, were killed and many more were injured.
Amnesty said that among the dead were 10 members of one family, seven of them children. Their home was destroyed in two airstrikes on August 6. It said bodies of mostly young men, most of them handcuffed and shot in the head, have been frequently found near the local headquarters of the powerful Air Force Intelligence, which is in a government-controlled area.
The uprising against Assad's regime began with largely peaceful protests but has since morphed into a civil war that has spread to almost all areas of the country.
In the Damascus suburb of Daraya, the Local Coordination Committees activist group said government shelling killed a mother and her five children. It said the six were members of al-Sheik family and had fled from their hometown of Maadamiyeh to escape the violence.
An amateur video showed the five children draped in shrouds with their faces showing during the funeral. The body of the mother was all covered.