Helicopter gunships bombarded a strategic town in northern Syria overnight and tanks moved close to the commercial hub of Aleppo, rebels said, but kept well clear of new Turkish air defences installed to curb Syrian action near its frontiers.

Turkish commanders inspected the missile batteries deployed on the border region on Thursday following Syria’s shooting down of a Turkish warplane a week ago, which has sharply raised tensions between the

two nations.

The Turkish deployments, a graphic warning to President Bashar Al Assad, coincide with rising violence across Syria and increasingly urgent international efforts to forge a peace deal as the nation slips into full-blown war.

As the Turkish-Syrian dimension ratcheted up further pressure, peace envoy Kofi Annan said yesterday he was “optimistic” that crisis talks in Geneva today would produce an acceptable outcome, which has so far proved elusive. Regional analysts said that while neither Turkey nor its Nato allies appeared to have any appetite to enforce a formal no-fly zone over Syrian territory, Prime Minister Tayyip Erdogan had made it clear Assad would be risking what he called the ‘wrath’ of Turkey if its aircraft strayed close to

its borders.

Recently, there were clashes close to the border between Syrian forces and rebels. Last weekend, Damascus said “terrorists” infiltrating from Turkey were killed and there have been reports of Syrian forces shooting into camps for refugees in Turkey.

The United States, Britain and France have said that Assad is responsible for the violence, which the United Nations estimates has killed at least 10,000 people, and is no longer fit to govern. Russia and China, however, reject what they describe as Western calls for “regime change”.

Turkey, sheltering some 34,000 Syrian refugees and providing bases for the rebel Free Syria Army (FSA), is in the forefront of the efforts to bring down Assad.

The British-based Syrian Observatory for Human Rights said 190 people, including 125 civilians, were killed on Thursday.

General Mustafa Al Sheikh, head of the Higher Military Council, a grouping of senior officers who defected from Assad’s forces, said around 170 Syrian tanks had assembled at an infantry school near the village of Musalmieh northeast of the city of Aleppo, just 30km from the Turkish border.

“They’re either preparing to move to the border to counter the Turkish deployment or attack the rebellious (Syrian) towns and villages in and around the border zone north of Aleppo,” Sheikh told Reuters.