By Michael Kahn, Supantha Mukherjee and Tom Balmforth PRAGUE/STOCKHOLM/LONDON, April 7 (Reuters) - Specialist mini jet engine makers across Europe are ramping up production and investment to head off a looming supply shortage that threatens to hold back Ukraine's rapid deep-strike drone programme at a critical stage of the war with Russia.

Ukraine Outpaces Russia In Drone Launches. For the first time since Russia launched its full-scale invasion in 2022 and began to pummel Ukraine

U.S. and European officials have told The Associated Press that Russia is sending a shipment of drones to Iran including upgraded versions of the drone technology that Tehran originally supplied to Moscow after its invasion of Ukraine.

Earlier this month, President Trump told journalists he didn’t want Ukraine’s assistance with drone defense, saying Ukrainian President Volodymyr Zelenskyy was the last person he’d ever ask for help.

Larger drones are being converted into motherships for FPVs, but small guided munitions may be a more effective payload.

Russia has unleashed a massive drone and missile barrage on civilian areas of Ukraine and is stepping up ground attacks along the front.

Ukraine has begun fielding acoustic sensor systems designed to detect low-flying drones earlier than conventional radar, a development that addresses one of the war’s most persistent tactical problems.