Syrian army tanks were seen pulling out of Homs on Tuesday as a team of Arab League peace monitors headed for a first look at the protest hotbed city where 34 people were reported killed in the previous 24 hours.

The British-based Syrian Observatory for Human Rights cited reports from opposition activists in Homs saying at least 11 tanks had left a district they attacked on Monday, and that other tanks were being hidden.

Opponents of President Bashar al-Assad say districts of Syria's third biggest city have been hammered by government troops and tanks in recent days, with the Baba Amr neighbourhood taking a pounding from tank fire, mortars and heavy machineguns.

My house is on the eastern entrance of Baba Amr. I saw at least six tanks leave the neighbourhood at around 8 in the morning (0600 GMT), Homs activist Mohamed Saleh told Reuters by telephone. I do not know if more remain in the area.

Amateur video recorded by activists on Monday showed tanks prowling around Baba Amr, firing at unseen targets. Video showed gruesome pictures of mangled bodies in the wreckage of building that bore the signs of shelling.

Arab League monitors were expected to see for themselves whether Assad is keeping his promise to cease military action against anti-government protests that began in March. At least 5,000 people have been killed in the crackdown by a U.N. count.

We are on our way to Homs, we are about to arrive, the head of monitoring mission Sudanese General Mustafa Dabi told Reuters by telephone.

Assad's opponents fear that the monitors - who arrived in the country on Monday after weeks of negotiations with Arab states - will be used as a cloak of respectability for a government that will hide the extent of violence.

The launch of the monitoring mission marks the first international intervention on the ground in Syria since the revolt broke out nine months ago. The government quickly cracked down on protests inspired by uprisings across the Arab world.

The first 50 of an eventual 150 monitors arrived on Monday. They will be split into five teams of 10. The teams will use government transport, according to Dabi, a move likely to fuel charges by the anti-Assad opposition that the monitoring mission will be impeded and hoodwinked from the outset.

Arab League delegates insist the mission will nevertheless maintain the element of surprise and be able to go wherever it chooses with no notice.

The monitors are meant to determine whether the government is abiding by a peace plan that requires it to withdraw troops from cities, free prisoners and open dialogue with its opponents. Assad has so far shown no sign implementing the deal.

At least 34 people were killed in Homs on Monday as tanks fired into districts where opposition has been strongest to Assad's rule, the Observatory said. Their names were recorded.

Amateur video posted by activists on the Internet showed tanks in action in Baba Amr, with bodies lying in pools of blood on a narrow street. Power lines had collapsed and cars were burnt and blasted, as if shelled by tank or mortar rounds.

What's happening is a slaughter, said Fadi, a resident living nearby.

Destruction inflicted by heavy weapons was evident. The video images were impossible to verify -- because Syria has barred most foreign media from the country -- but hard to fake.

Assad says he is fighting Islamist terrorism directed from abroad and that some 2,000 people have been killed, mainly soldiers and police.

AVERTING CIVIL WAR

An armed insurgency is eclipsing civilian protest in Syria. Many fear a slide to sectarian war between the Sunni Muslim majority, the driving force of the protest movement, and minorities that have mostly stayed loyal to the government, particularly the Alawite sect to which Assad belongs.

Analysts say the Arab League is anxious to avoid civil war. Western powers have shown no desire to intervene militarily and the United Nations Security Council is split.

Assad's opponents appear divided on aims and tactics. He retains strong support in important areas -- including Damascus and the second city Aleppo -- of the country, which lies at a volatile nexus of Middle East conflict.

Fighting in Homs has intensified since a double suicide bombing in Damascus on Friday that killed 44 people.

At least ten army defectors were killed in fighting with security forces in the suburb of Douma outside Damascus, according to the British-based Syrian Observatory for Human Rights. The group estimated the death toll may be higher, in the dozens, with casualties at a similar rate among security forces.

Homs resident Fadi told Reuters via Skype that residents and rebel fighters were trapped by trenches the army had dug around the Baba Amr neighbourhood in recent weeks.

They are benefiting from trenches. Neither the people nor the gunmen or army defectors are able to flee. The army has been descending on the area for the past two days.

Others said the army was also taking a hit.

The violence is definitely two-sided, said a Homs resident who gave his name only as Mohammed to protect his safety. I've been seeing ambulances filled with wounded soldiers passing by my window in the past days. They're getting shot somehow.

Parts of Homs are defended by the Free Syrian Army, made up of defectors from the regular armed forces, who say they have tried to protect civilians.

(Writing by Douglas Hamilton)