Syria rebels accused of massacring 25 people in village
At least 25 people have been killed and their bodies mutilated by "terrorists" in northern Syria, state media report.
The Sana state news agency cited sources as saying the victims had been abducted earlier on Friday from Darat Izza, a village in Aleppo province.
Activists said 26 government supporters had been shot dead by rebels.
The joint UN-Arab League envoy on Syria Kofi Annan said it was "time for countries of influence to raise the level of pressure" over Syria.
Mr Annan, who has seen his six-point plan to end the conflict unravelled by violence, said the time to act was now - the process could not be open-ended.
Russia's foreign minister met his Syrian counterpart earlier urging Damascus to do more to implement Mr Annan's peace plan, under which a ceasefire came into force in April.
The UN says 1.5 million people are in need of humanitarian aid in Syria - an increase of 500,000 on its previous estimate.
The Office for the Co-ordination of Humanitarian Affairs said more and more were fleeing their homes because of the fighting between security forces and rebels, and that it was seriously hampering aid deliveries.
In other developments:
- Turkey's military says it has lost contact with one of its aircraft over the sea close to the border with Syria - Turkish media say the F-4 jet crashed in Syria or Syrian territorial waters
- The head of the Syrian Olympic Committee is refused a visa to travel to the UK to attend the Games
A video purportedly showing the aftermath of the killings in Darat Izza, which was posted online on Friday, showed the bodies of more than a dozen men piled on top of each other. At least two of the victims were wearing uniform.
"These are shabiha of Bashar al-Assad's regime," the narrator said, referring to the opposition's name for pro-government militiamen.
The narrator said they had been killed by the rebel Free Syrian Army (FSA) while trying to attack the area alongside troops, tanks and helicopters.
The official sources cited by state TV and Sana did not say if those killed had been supporters of the president, only describing them as "citizens".
"The sources confirmed that the terrorist groups in Darat Izza committed a brutal massacre against the citizens, whom they had kidnapped earlier on the day, through shooting them dead and then mutilating their bodies."
"The sources added that initial information indicates that more than 25 of the kidnapped citizens were killed in Darat Izza massacre, with the fate of the rest of the kidnapped people is still unknown," Sana reported.
The UK-based Syrian Observatory for Human Rights said at least 26 "supporters of the regime - believed to be militiamen - were shot dead".
It added that the area had been under bombardment by government troops for several weeks as they try to regain areas controlled by rebels.
However the men died in Darat Izza, the incident is likely to further envenom the climate in what many now believe has already become a civil war, says the BBC's Jim Muir in Beirut.
It overshadowed continuing violence in other places, our correspondent adds. In the city of Aleppo, activists said at least 10 people were killed when security forces opened fire on a demonstration in the city centre after Friday prayers.
The Syrian Observatory also reported that four senior army officers - two brigadiers and two colonels - had defected and published a video purportedly showing them declaring that they were joining the opposition.
On Thursday, a fighter pilot flew his MiG-21 jet to a military airbase in neighbouring Jordan, where he was given asylum. It was the first time a Syrian air force pilot has defected with his plane since the protests against President Assad began in March 2011.
The UN says at least 10,000 people have died since pro-democracy protests began in March 2011. In April, the Syrian government reported that 6,143 Syrian citizens had been killed by "terrorist groups".
The UN Office for the Co-ordination of Humanitarian Affairs (OCHA) said on Friday that the number of people needing humanitarian assistance had risen to 1.5 million. They included 350,000 in the northern province of Idlib and 250,000 in the central city of Homs, it added.
The UN's World Food Programme (WFP) had distributed food to 461,000 people by mid-June and planned to reach 850,000 in July, it added.
The BBC's Imogen Foulkes in Geneva says the world's biggest aid agencies have been virtually powerless to help those in need of assistance in Syria.
An agreement between the UN and the Syrian government on mounting a major aid operation, announced only two weeks ago, has so far not got off the ground, our correspondent says.
The OCHA had planned to set up field offices in Homs and in the eastern city of Deir al-Zour, but it said the deteriorating security situation meant those plans were on hold.
Medical care is a particular concern, our correspondent adds. A World Health Organisation (WHO) assessment of Syrian hospitals found half were not fully functioning.
The International Committee of the Red Cross (ICRC) - the only international aid agency operating in Syria - is still waiting to enter Homs, where it is believed hundreds of people, many of them wounded in recent shelling by the military, are trapped.