Syrian troops pounded opposition areas on Saturday, activists said, killing 43 people in an offensive that has sent thousands of refugees surging into Turkey before next week's U.N.-backed ceasefire aimed at staunching a year of bloodshed.
Each side has accused the other of intensifying assaults in the run-up to the truce due to take effect early on Thursday if government forces begin pulling back from towns 48 hours earlier in line with U.N.-Arab League envoy Kofi Annan's peace plan.
The military attacked Deir Baalba district in the restive city of Homs, killing 17 people in what the grassroots Local Coordination Committees opposition group called a massacre.
Amateur video recorded by activists showed scenes of carnage said to be the aftermath of the assault. Heaps of mangled limbs and body parts gathered in blankets were being loaded onto a pick-up truck after army shelling. The footage, which could not be verified independently, also showed 13 people who had apparently been tied up and had their throats cut.
No comment was immediately available from Syrian officials.
The Syrian Observatory for Human Rights said at least 43 people had been killed, including 27 in an army attack on al-Latmana, a town in Hama province, that began on Friday.
Rebels trying to oust President Bashar al-Assad attacked army posts north of Aleppo after midnight, killing an officer and two men, and assaulted a helicopter base, activists said.
Syrian commandos shot dead three rebels in an overnight raid on a terrorist den, Syria's state news SANA agency reported.
The towns of Anadan and Hraytan north of Aleppo and the countryside around Syria's second city have endured days of clashes and bombardment, prompting 3,000 civilians to pour across the Turkish border on Friday alone - about 10 times the daily number before Assad accepted Annan's plan 10 days ago.
BAATH PARTY ANNIVERSARY
The Syrian leader is fighting a popular uprising, which he blames on foreign-backed terrorists, that has spawned an armed insurgency in response to violent repression of protests.
While many in Syria's Sunni Muslim majority back the revolt, especially in provincial areas, Assad retains support from his own minority Alawite sect and other minorities fearful that his overthrow would lead to civil war or Islamist rule.
In Damascus, thousands of flag-waving Assad supporters marked the founding in 1947 of Syria's ruling Baath Party.
The bloodletting of the past week or so does not bode well for implementation of Annan's ceasefire plan.
This requires Assad to begin pullback of military concentrations in and around population centres by Tuesday.
Rebel Free Syrian Army commander Colonel Riad al-Asaad said his men would cease fire, provided the regime ... withdraws from the cities and returns to its original barracks.
Syria has said the plan does not apply to armed police, who have played a significant role in battling the uprising in which security forces have killed more than 9,000 people, according to U.N. estimate. Syria says its opponents have killed more than 2,500 troops and police since the unrest began in March 2011.
Annan's plan does not stipulate a complete army withdrawal to barracks or mention police.
Satellite pictures published by U.S. ambassador Robert Ford showed Syrian artillery apparently still poised to target built-up areas and tanks being moved from one place to another.
This is not the reduction in offensive Syrian government security operations that all agree must be the first step for the Annan initiative to succeed, Ford said in Washington.
U.N. Secretary-General Ban Ki-moon demanded that the government halt attacks on civilians and keep its promises.
The 10 April timeline ... is not an excuse for continued killing, he said on Friday. The Syrian authorities remain fully accountable for grave violations of human rights and international humanitarian law. These must stop at once.
(Writing by Douglas Hamilton; Editing by Alistair Lyon)