TEHRAN, June 30 (Xinhua) -- About 15 people are feared to have lost their lives in an explosion of natural gas tanks in a city west of Tehran, Iran's satellite Press TV said on Monday.

    The explosion ripped through the Mohammad-Shahr gas processing plant at about 22:00 local time (1930 GMT) Sunday in the city of Karaj, said the report.

    An undisclosed number of gas tanks blew up on the heels of the initial explosion, adding to the intensity of the blast, Press TV said.

    The cause of the explosion has not yet known, said Press TV.

    Mohammad-Shahr is a small town on the outskirts of Karaj, the second most heavily populated city of Iran, which lies some 45 km to the west of Tehran.