In an effort to halt the fighting in Aleppo, US Secretary of State John Kerry has held fresh talks with his Russian counterpart Sergei Lavrov. But no breakthrough emerged.

The meeting in Germany on Wednesday evening lasted about an hour, and Kerry said the two exchanged ideas about the "extraordinarily dire situation" in Aleppo, and intend to "connect in the morning".

The two foreign ministers met before the start of the two-day Organization for Security and Cooperation in Europe meeting chaired by Germany.