Army defectors killed at least 27 soldiers and security service agents south of Damascus on Thursday in the third straight day of regime losses as the uprising in Syria entered its 10th month.
The clashes in Daraa province where protests against Bashar al-Assad's regime first erupted in mid-March came as Human Rights Watch said that half of the more than 60 rebel soldiers it interviewed for a new report said they had mutinied after receiving direct orders to shoot on civilians.
Burhan Ghaliun, head of the Syrian National Council (SNC), the country's most representative opposition grouping, said he hoped it would not be long before the UN Security Council took action after UN chief Ban Ki-moon urged world powers to act "in the name of humanity."
Thursday's fighting broke out at dawn at checkpoints in three separate places in Daraa province, the Britain-based Syrian Observatory for Human Rights said in a statement sent to AFP in Nicosia.
The clashes came after army defectors killed at least eight loyalist troops on Wednesday and seven on Tuesday as they stepped up attacks that they have said were reprisals for security force attacks on civilians.
Human Rights Watch named 74 military and intelligence officers "who allegedly ordered, authorised, or condoned widespread killings, torture, and unlawful arrests" in its report entitled: "By All Means Necessary."
"Defectors gave us names, ranks, and positions of those who gave the orders to shoot and kill," said Anna Neistat, the New York-based watchdog's associate director for emergencies.
"Each and every official named in this report, up to the very highest levels of the Syrian government, should answer for their crimes against the Syrian people", Neistat said, urging the UN Security Council to refer the case to the International Criminal Court.
Because Syria is not an ICC member, the court can only intervene after a Security Council referral, a move that would be subject to a veto by permanent members China and Damascus ally Russia.
Russia, which along with China blocked a resolution condemning Assad in October, said this week the West is pursuing an agenda of "regime change" by putting pressure on Damascus but not on armed groups.
The US State Department's special coordinator on Middle East affairs, Frederic Hof, said on Wednesday that it was vital that Moscow and Beijing change their stance.
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"We ask those governments that are insulating this regime from the will of Syria's citizenry: do not make innocent civilians pay the price for your political calculations," Hof said.
Ban told reporters in New York that the status quo in Syria -- where the UN estimates that more than 5,000 people have been killed in the regime's crackdown -- "cannot go on."
"In the name of humanity, it is time for the international community to act," said the UN secretary general.
In message to "revolutionaries" inside Syria posted on opposition websites on the eve of a three-day SNC congress in Tunisia, its leader said he expected the Security Council to adopt an Arab League blueprint for an end to the bloodshed.
"I hope that before too long we will succeed in persuading the Security Council to adopt the Arab League plan and provide the international protection for civilians that we have been demanding," Ghaliun said.
Arab foreign ministers are to hold an emergency meeting in Cairo on Saturday to respond to Syria's proposal to admit observers in exchange for an end to the sweeping sanctions the 22-member bloc decided to impose on November 27.
Iraq is to send a delegation to Syria in its own initiative to end the bloodshed in its western neighbour, Prime Minister Nuri al-Maliki said as he flew home from Washington on Thursday.
"When I arrive in Baghdad, I will hold a meeting to prepare the plans to send a delegation to Syria in order to implement the Iraqi initiative," Maliki told AFP in an exclusive interview.
"America and Europe are afraid of the phase after (Syrian President) Bashar al-Assad. That is why they (the United States and Europe) understand the initiative," he said.
Iraq has expressed mounting concern over the potential for the violence to spill over the border and has declined to enforce the Arab League sanctions citing its close ties with Syria.
During a visit to Baghdad by Arab League chief Nabil al-Arabi last week Foreign Minister Hoshyar Zebari said Iraq was keen to do all it could to support the bloc's efforts to end the bloodshed.
"We can help, we can play a useful role to support the Arab initiative," he told a news conference.