The U.S. is scrambling to contain a worsening clash between two of its military partners in Syria, as the country’s new government battles a Kurdish militia in the city of Aleppo.Lethal fighting raged Thursday between the two sides in the divided city where Kurdish-led forces hold key neighborhoods.

Syrian army has given SDF fighters a new deadline to lay down the arms and has also warned of imminent attacks targeting them in Sheikh Maqsoud area.

The fighting, which erupted on Tuesday, has driven more than 140,000 people from their homes and left at least seven civilians dead, according to Syrian authorities.