A Russian Sukhoi Su-30 fighter jet that crashed this week may have been accidentally shot down by another plane during exercises, the state-run TASS news agency reported Wednesday.

The Su-30 was on a routine training mission with two pilots on board Tuesday when it crashed near a village in the Tver region northwest of Moscow. The pilots ejected before the crash and were soon evacuated by a search and rescue helicopter.

“The preliminary cause of the accident is a missile accidentally hitting the Su-30 during exercises,” an unnamed source in the regional emergency services told TASS.

“The shot was fired by another aircraft,” they added. 

The Defence Blog military news website previously reported, citing unnamed sources, that an Su-35 fighter jet may have fired at the Su-30. 

The TASS source said the Su-30 pilots were in stable condition.