An aid convoy carrying humanitarian supplies for 50,000 displaced people has arrived in Afrin in Syria, the International Committee of the Red Cross said on Thursday, as Turkey wages an offensive in the area.

The situation in Afrin and other areas along the Syria-Turkish border is alarming, with the majority of people living in "dire conditions," the ICRC said in a statement.

"Only four hospitals are operating in the area. Medical staff are overwhelmed and struggling to cope with the increase in casualties," it said, adding that some people needing medical care were reportedly trapped in certain areas of Afrin.