US SECRETARY of State John Kerry appeared yesterday to back Syrian extremists who stormed out of Geneva peace talks.

His comments came a day after Syrian troops — backed by Russian air strikes — broke Nusra Front lines north of Aleppo city to lift the three-year siege of the pocket of resistance around Zahraa.

The High Negotiating Committee (HNC) — a Saudi-convened delegation from dozens of the al-Qaida affiliate’s terrorist allies — responded by walking away from the already stalled negotiations.

The HNC had refused to meet the Syrian government delegation until all attacks against its forces were ended and supplies were allowed into the areas they hold.

In London, a 70-nation conference to raise aid donations for Syria heard Mr Kerry call on Syria and Russia to end attacks on insurgent-held areas and allow supply convoys in.

UN general secretary Ban Ki Moon said: “It is deeply disturbing that the initial steps of the talks have undermined by the continuous lack of sufficient humanitarian access, and by a sudden increase in aerial bombing and military activities within Syria.”

Mr Kerry had earlier met British Foreign Secretary Phillip Hammond and their counterparts from rebel backers Qatar and Turkey, along with Germany, France, Italy and the UAE for breakfast.

Mr Hammond said the ministers had discussed “the stabilisation and reconstruction of Syria once Assad has gone and the new Syria can be built,” sticking to the fading hope of ousting the Syrian president.

Mr Kerry later spoke with Russian Foreign Minister Sergey Lavrov, the two agreeing to co-ordinate UN aid deliveries by air.

Elsewhere, Mr Lavrov predicted the imminent defeat of Islamic State (Isis) in line with UN security council resolution 2254.

Residents of Zahraa and nearby Nubl celebrated the lifting of the siege.

The victory has turned the Nusra-held supply corridor to Turkey through Azaz into a cul-de-sac.

Yesterday, Kurdish Peoples’ Protection Units (YPG) militia forces on the west flank of the Azaz corridor seized the villages of Ziyarah, Khuraybah and Mayer north of Zahraa, with the aid of Russian air strikes.

And, east of Aleppo, government forces advanced on Tayyibah, closing a pincer on Isis forces around the thermal power plant.

Turkish Prime Minister Ahmet Davutoglu told the London conference that tens of thousands of refugees were fleeing the fighting in the south.