BERLIN (AP) — Germany's foreign minister says humanitarian aid is desperately needed in the besieged Syrian city of Aleppo and that it may be necessary to start an "air bridge" to bring it in.

Minister Frank-Walter Steinmeier told the Welt am Sonntag newspaper on Saturday that Germany was in talks with the U.S., Russia and the United Nations to try and organize "urgent humanitarian assistance" to the northern Syrian city.

Despite calls for a cease-fire and Russia's promise of a three-hour daily respite from airstrikes to allow in humanitarian aid, there has been no letup in the violence.

Steinmeier says "if both parts of Aleppo continue not to receive sufficient humanitarian supplies, we should also consider the possibility of assistance by air, especially medical goods."