The jet crashed inside Kandahar Airfield during takeoff at 7:20 a.m. Afghanistan time (0250 GMT), said Capt. Ruben Hoornveld, a spokesman for the NATO-led force. The two-member crew ejected and were being treated at the base hospital.
There was no indication that insurgent activity caused the crash, he said, but officials could not immediately say why the plane went down. The jet caught fire and emergency personnel responded.
NATO didn't identify which nation the jet came from, but a U.S. military spokeswoman in Kabul, Lt. Cmdr. Christine Sidenstricker, said the jet was a Tornado - an aircraft commonly flown by British forces.
The crash happened one day after a Russian-owned civilian Mi-8 helicopter crashed at Kandahar Airfield, killing 16 people on board. Both Kandahar crashes follow a string of deadly aircraft downings elsewhere around Afghanistan in recent days.
Hoornveld said he did not know why two aircraft had crashed in Kandahar in two days.
"Honestly I can't say, but from my personal view it's coincidence," he said.
Afghan police and NATO troops closed down the highway that runs by the base, and emergency personnel cordoned off the crash site and evacuated the surrounding area, Hoornveld said.
The crash of the Tornado is the third aircraft to go down in Afghanistan in three days. A U.S. Air Force F-15E Strike Eagle fighter jet crashed early Saturday in central Afghanistan, killing two crew members. U.S. officials say insurgent fire did not bring down the plane.
Last week, Taliban militants downed an Mi-6 transport helicopter in southern Afghanistan, killing six Ukrainian civilians on board and an Afghan child on the ground.
Earlier in July, two Canadian soldiers and one British trooper were killed in a helicopter crash in Zabul province. Officials said that crash did not appear to be a result of hostile fire.