Syrian forces spread across the city of Deraa on Monday after overnight clashes there and pursued clean-up operations in Homs, where the Red Cross was still seeking access to a former rebel bastion.
Syria has so far brushed off international pressure to halt nearly a year of bloodshed since the first protests against President Bashar al-Assad erupted in Deraa last March, touching off an uprising inspired by others in the Arab world.
The United Nations-Arab League special envoy to Syria, Kofi Annan, will travel to Damascus on Saturday for what would be his first visit since he was appointed to the post last month.
Kofi Annan told me that Syria will receive him on March 10 and that he would arrive in Cairo on March 7, the Arab League Secretary-General Nabil Elaraby said in Cairo.
China also said it would send an envoy to Syria to try to halt a conflict that has divided Beijing from Western and Arab powers demanding stronger action against Assad.
Hundreds of troops and security men fanned out in Deraa on a scale not seen for months, a resident of the southern city said.
The clampdown followed attacks on security checkpoints in the city centre that were also the most extensive for months. At least one person was killed, the Deraa resident told Reuters.
Outgunned rebels have multiplied hit-and-run assaults across Syria in the last few days to signal their defiance after the military overran the Baba Amr district of Homs.
A bomb explosion hit an oil pipeline in Syria's eastern province of Deir al-Zor on Monday as Syrian troops began a sweep in the region, opposition activists said.
Syrian armoured forces recaptured Baba Amr from its lightly armed defenders on Thursday after an almost month-long siege in which shelling reduced much of the district to rubble.
The International Committee of the Red Cross and the Syrian Arab Red Crescent were still seeking approval from Syrian authorities to enter Baba Amr to help civilians there.
Teams from the two agencies distributed food and blankets to civilians, including families who had fled Baba Amr, in two neighbourhoods of Homs, ICRC spokesman Hicham Hassan said.
An ICRC convoy carrying food for several thousand people and other relief supplies had also arrived in Homs from Damascus, the second in less than a week, he said in Geneva.
Opposition activists have accused Syrian forces of carrying out bloody reprisals in Baba Amr, but their reports are hard to verify given Syria's severe curbs on independent media.
Human Rights Watch quoted local sources on Friday as saying about 700 civilians had been killed and thousands wounded in Homs since a military assault in the city began on February 3.
The state news agency SANA said the authorities had begun to remove destruction and debris left by armed terrorist groups in Inshaat and Baba Amr neighbourhoods in Homs on Sunday.
It said 16 members of the security forces killed by insurgents had been buried the same day.
The British-based Syrian Observatory for Human Rights said the security forces had killed 29 people across Syria on Sunday. The Local Coordination Committees, a grassroots opposition group, put the death toll at 62, including 17 in Homs.
The United Nations refugee agency said on Sunday up to 2,000 Syrians were fleeing into neighbouring Lebanon, but it was not immediately clear how many had actually crossed the border.
Lebanon hosts more than 7,000 registered refugees from Syria. Turkish leaders say about 12,000 Syrians, half of them not registered at camps, have fled to their country.
DISCORD OVER SYRIA
The world has failed to agree on how to halt the violence in Syria. Last month China and Russia vetoed a U.N. Security Council draft resolution that would have backed an Arab League call for Assad to step down as part of a political transition.
Assad has rejected the plan, saying he is pressing ahead with his own political reform timetable, which includes a multi-party election within three months based on a new constitution.
Saudi Arabia and Qatar are among countries that have called for Syrian rebels to be armed, but there is little appetite in the West for Libya-style military intervention that could have many unforeseen consequences in the conflict-prone Middle East.
Riyadh and Doha ... remain unlikely to share Western fears about worsening the situation in Syria, said David Hartwell, senior Middle East analyst at IHS Janes, adding that recent setbacks for the rebel Free Syrian Army might strengthen the Gulf Arab hawks' case for supplying it with weapons.
To do so carries no guarantee of success and would require both countries to convince a nervous Turkey -- through which any weapons supplies would likely be channelled -- that such a move is a diplomatic and military gamble worth taking, Hartwell said, noting that Ankara had so far resisted such arguments.
Russian Foreign Minister Sergei Lavrov will join Arab counterparts in Cairo this month to discuss Syria.
And China's former ambassador to Damascus, Li Huaxin, will go to the Syrian capital on Tuesday to discuss a six-point Chinese plan, the Chinese Foreign Ministry said.
Although conditions are extremely complicated, and the situation remains tense, China still maintains that a political solution offers the fundamental escape from the Syrian crisis, Foreign Ministry spokesman Liu Weimin said.
The United Nations says Syrian security forces have killed more than 7,500 civilians since the revolt against the Assad family's four-decade rule began in March last year.
Several Arab and Western countries have pulled their diplomats out of Syria and imposed sanctions in protest.
Air France cancelled its Damascus flight on Monday for security reasons, a spokeswoman said without giving details. The airline has yet to decide on this week's remaining flights.
(Additional reporting by Khaled Yacoub Oweis in Amman, Afif Diab on Lebanese border, Stephanie Nebehay in Geneva, Tim Hepher in Paris and Chris Buckley in Beijing; Writing by Alistair Lyon, editing by Peter Millership)