Turkish jets strike Kurds in Syria as the US urges calm

Turkish war planes have carried out air strikes on Kurdish positions in northern Syria, in a move likely to anger its US allies.

Turkey is seeking to oust Kurdish fighters from the Afrin province, which he fighters have controlled since 2012. Some of the Kurdish forces had helped the US to fight the Islamic State group.

Reports also say that pro-Turkish Syrian rebels are advancing on the city.

Turkey says it is launching a full military operation against the Kurds - which it considers a terrorist group.

Turkish President Recep Tayyip Erdogan has also threatened the city of Manbij - some 100km away from Afrin in another Kurdish area – singling it out as a possible next target.

Russia - a key military figure in the region - says it is concerned by the reports, but has stuck to its position of non-intervention in the conflict.

Syria has previously warned against any such operation and warned that it would shoot down Turkish planes.

The Kurdish YPG (Syrian Kurdish People's Protection Units) has been a key part of the battle against the group calling itself the Islamic State in Syria, and enjoys backing from the United States.

Turkey, however, believes the group has links to the banned Kurdistan Workers Party (PKK), and has been threatening to clear Kurdish fighters from both Afrin and Manbij for several months.

The US recently announced that it will help the Syrian Democratic Forces (SDF) - an alliance against IS of which the YPG is a member – to build a new "border security force" to prevent the return of IS. Although President Erdogan called the border force a “terror army”, the YPG and SDF deny any terrorist links.

Disagreement over the Kurdish fighters has created a sharp division between the US and Turkey, who are both part of the NATO alliance.

The US state department has appealed for calm, and has attempted to downplay talk of a new "border force", instead characterising the new development as security training.