The leader of Lebanese Islamist group Hezbollah said that both Turkey and Saudi Arabia are driven by their "hatred" for the Syrian regime after the rebel groups they support in the civil war suffered successive defeats.

Sayyed Hassan Nasrallah says talk that Ankara and Riyadh plan to send troops into Syria to fight "Islamic State" (IS) militants was a "pretext" to launch a ground operation in Syria and then "gain a foothold" in the country.

Nasrallah, who was addressing supporters in Beirut by satellite from his hideout, said the two countries favored a prolonged war in Syria rather than agreeing to a settlement which would lead to President Bashar al-Assad staying in power.

Hezbollah fighters operate in Syria fighting alongside Assad's forces.

Turkey won't go it alone

Meanwhile, Turkish Foreign Minister Mevlut Cavusoglu told Reuters that calls for a ground operation went further than Ankara and Riyadh.

"Some countries like us, Saudi Arabia and some other Western European countries have said that a ground operation is necessary. But...if such an operation is to take place, it has to be carried out jointly, like the [coalition] air strikes," he said.

Another Turkish official - speaking on condition of anonymity - was cited by the Associated Press on Tuesday as ruling out the possibility of Turkey undertaking unilateral action or the prospect of a joint Saudi-Turkish venture without broader consensus.

Russia has warned that a foreign invasion of Syria would lead to decades of war.

Hospital strike condemned

Meanwhile, Moscow faced accusations that its air force had targeted a Doctors Without Borders hospital in northern Syria on Monday.

Turkey and France described the bombing of the medical facility in Idlib as war crimes.

Seven people were killed and another eight are presumed dead following the attack.

War on Turkey's border

The Syrian Observatory for Human Rights said at least 15 people were killed on Tuesday when US-led airstrikes hit a bakery in the northeastern city of al-Shadadi.

Those killed were civilians who had gathered outside the shop at dawn to buy bread, the monitoring group added.

Syrian government forces made fresh advances on Tuesday in northern Aleppo province at the expense of rebels whose positions have been collapsing in recent weeks under the Russia-backed onslaught.

Supported by Iranian-backed Shiite militias as well as Russian airstrikes, they brought the conflict to within 25 kilometers (15 miles) of the Turkish border.

Meanwhile, Kurdish fighters, regarded by Ankara as hostile insurgents, have extended their presence along the border, with Turkish artillery returning fire into Syria for a fourth straight day on Tuesday.

Hope for desperate civilians

Also on Tuesday, the United Nations said the Syrian government had approved access for the delivery of humanitarian aid to seven besieged areas.

A UN spokesman said aid teams and other partners were preparing convoys and would depart within the coming days for Deir el-Zour, Foua and Kfarya in Idlib, and Madaya, Zabadani, Kfar Batna and Moadamiyeh in rural Damascus.

Humanitarian access to besieged areas is part of the agreement reached by 17 key nations in Munich on February 12.

mm/cmk (AFP, AP, Reuters)