"We must not allow the internal Syrian dialogue process to be torpedoed from the outside," Annalena Baerbock told a Berlin press conference.

"Neighbours such as the Turkish and Israeli governments, which are asserting their security interests, must not jeopardise the process."

Since Assad's downfall, Israel has launched strikes on military sites in Syria ranging from weapons depots to naval vessels, according to the Syrian Observatory for Human Rights war monitor.

Israel has also sent troops into a UN-patrolled buffer zone east of the Israeli-annexed Golan Heights.

Turkey meanwhile is worried Kurdish separatists could take advantage of Assad's ouster to extend their influence in Syria, where they have dominated a large northeastern area since 2012.

Ankara sees the Kurdish forces, notably the militant group YPG, as an extension of the banned Kurdistan Workers' Party (PKK), which has fought an insurgency against the Turkish state since the 1980s.

Since Assad fled, Turkish-backed groups have launched offensives in northern Syria, though the Kurdish-led force there said Wednesday fighting had stopped under a US-brokered ceasefire.

Baerbock said Syria's "new chapter" was still being written, adding that "the outcome of the revolution is not certain, nor have the people won the transition to a free and peaceful Syria".

"Syria must not be allowed to become a pawn in the hands of foreign powers or forces again," she added.

During Assad's rule, Syria was backed by Iran and Russia, whose intervention in 2015 turned the tide of the civil war.

Speaking on a trip to Jordan, German Defence Minister Boris Pistorius said Israel's strikes "can be understood as a measure for security".

"Nobody really knows who will ultimately have control of the country," Pistorius said.

"The idea that gas weapons from Syrian factories could fall into the wrong hands and play a role in Islamist-motivated attacks somewhere in the world is an idea that would be unbearable."

By the same token, he said, it was incumbent upon Israel not to "contribute to escalation".