KARACHI, Pakistan (AP) _ A Pakistan navy aircraft crashed into the Arabian sea today killing all 21 military personnel on board, said a navy official.

The P-3C Orion American-made aircraft was on a regular reconnaissance flight over the coastal regions of southwestern Baluchistan province when it crashed, said officials.

Officials said the cause of the crash was being investigated.

The aircraft disappeared from radar screens shortly after it took off this morning, officials said.

A search and rescue operation was launched and the wreckage of the aircraft was found six hours later near Pasni in Baluchistan, 210 miles west of the southern port city of Karachi.

The $140 million aircraft was originally purchased in 1989, but was not delivered because of U.S. sanctions against Pakistan that took effect in 1990.

In 1996 an exception was made and three of the aircraft were delivered.