Russian cargo planes left Tehran 10 days ago with UAVs, some of which have already malfunctioned, U.S. and allied officials say Russian cargo planes have quietly picked up the first of scores of Iranian-made combat drones for use against Ukraine, U.S. officials said, in a move that underscores deepening ties between Moscow and Tehran while also highlighting Russia’s struggles to supply its overstretched military. But while the weapons could provide a significant boost for Russia’s war effort against Ukraine, the transfer has been marred by technical problems, security officials from the United States and an allied government said in interviews....