PRAGUE (Reuters) - Two Czech military jets collided in a training exercise and debris fell on a residential area, but the airmen survived and there were no casualties on the ground, Czech Radio reported on Monday. It said the two MiG-21s crashed and debris from one of the planes fell into a residential area in the southern city of Ceske Budejovice. The three airmen were alive but sustained injuries. A Czech radio reporter on the scene said that a fire had broken out in an apartment block that was hit by wreckage, and residents had been evacuated. Some people were being treated with oxygen after breathing poisonous fumes from the fire. A spokesman for the Czech Air Force confirmed to Reuters that the crash happened at 9.29 a.m. (0729 GMT) and that there were no civilian casualties. No further official information was available. Czech Radio reported that the three airmen — two pilots and a crewman in one of the planes — had ejected.