Protests against president Bashar al-Assad erupted in several Syrian cities today, activists said, and the Arab League chief said he feared the bloody unrest could degenerate into a civil war with ill effects for the wider region.
Security forces killed one demonstrator in the northwestern town of Idlib, the Syrian Observatory for Human Rights said.
Protests also flared after Friday prayers in some areas of the capital Damascus, as well as the port city of Latakia, where Arab League monitors had come under attack from a pro-Assad crowd on Monday. "The people want the downfall of the regime!" people chanted near a Latakia mosque, one activist said.
Syrians determined to end four decades of Assad family rule have kept up protests since March despite a fierce crackdown by Dr Assad's military and security forces that the United Nations says has cost more than 5,000 lives.
Some, including army deserters, have taken up arms in recent months. Syrian authorities say foreign-backed "terrorists" have killed 2,000 soldiers and police since the revolt began.
The most senior Syrian officer to defect to the opposition said that desertions were wearing down the army, but that rebels could take more than a year to topple Dr Assad.
General Mostafa Ahmad al-Sheikh said that up to 20,000 soldiers, mostly majority Sunni Muslims, had left despite "iron controls", although most were more focused on evading capture by the secret police than on fighting the security forces.
The revolt is likely to take longer than those that toppled the autocratic rulers of Libya, Egypt and Tunisia because Dr Assad retains the loyalty of highly trained and well equipped forces from his minority Alawite sect, Gen Sheikh said.
"If we get 25,000 to 30,000 deserters mounting guerrilla warfare in small groups of six or seven it is enough to exhaust the army in a year to a year-and-a-half, even if they are armed only with rocket-propelled grenades and light weapons," he said in a telephone interview from south Turkey yesterday.
Video footage posted on the Internet today showed the burning hulk of an armoured personnel carrier on a street in Homs, a hotbed of protests and armed resistance to Dr Assad. A voice on the clip said the Free Syrian Army mounted the attack.
Armed clashes, now punctuating what began as a non-violent protest movement, have raised fears of a full-scale conflict in Syria, which also has Christian and Kurdish minorities.
"Yes I fear a civil war and the events that we see and hear about now could lead to a civil war," said Nabil Elaraby, head of the Arab League, which deployed monitors on Dec. 26 to check whether Syria was respecting an Arab peace plan.
"Any problems in Syria will have consequences for the neighbouring states," he told Egypt's Al-Hayat television.
Syria, which borders Lebanon, Turkey, Iraq, Jordan and Israel, is at the heart of a conflict-prone Middle East, where its closest allies are Iran and the Lebanese Hezbullah group.
Mr Elaraby described reports from the chief of the monitoring mission as "worrying", but said there was "no doubt that the pace of killing has fallen with the presence of the observers".
That contradicts the view of a senior UN official who told the Security Council this week that the rate of killings had accelerated to about 40 a day since the Arab monitors arrived, according to Washington's ambassador to the world body.
The British-based Observatory said at least 21 people were killed yesterday, including seven in the eastern city of Deir al-Zor and seven security force members in Maarat al-Noman.
Syrian opposition groups, and at least one disgruntled monitor, say the League mission has only bought Dr Assad more time.
Arab foreign ministers are to due to hear a report from the monitors on January 19th. "They will decide whether there is any benefit in continuing or not," said Mr Elaraby.
The observers resumed work yesterday, a League official said, for the first time since 11 were hurt in Latakia in an attack that also sidelined plans to expand the 165-strong team.
UN Secretary-General Ban Ki-moon, starting a visit to neighbouring Lebanon, told a Beirut daily he had repeatedly urged Syria to halt killings that have turned unrest against Dr Assad into one of the bloodiest of Arab uprisings.
"The Syrian authorities must respond to the legitimate democratic aspirations of the Syrian people," he told an-Nahar, adding that the Security Council, so far divided over Syria, should find a way to speak with one voice on the issue.
Russia and China have blocked any firms Security Council action against Syria. The Arab League has said that if the monitors' report next week is negative, it may refer Syria to the Security Council.
The Arab League is divided over Syria, with Qatar its most vocal critic and Algeria defending steps taken by Dr Assad.