¡¡¡¡BAGHDAD, Nov. 8 (Xinhuanet) -- A US Black Hawk helicopter which crashed in Iraq on Friday and killed all six people aboard was shot down, the US military confirmed Saturday.

¡¡¡¡"We believe it was brought down by ground fire," a military spokesman said in Tikrit, verifying the speculation that the helicopter had been hit by projectile, probably a rocket-propelled grenade (RPG).

¡¡¡¡Witnesses said they heard a sound of explosion before they saw the aircraft go down and crash into the river bank of the Tigris, only one km away from the headquarters of the US 4th Infantry Division in Tikrit.

¡¡¡¡The six soldiers on board were all killed, bringing to at least 149 the number of US soldiers killed by hostile fire since US President George W. Bush declared the major combat over on May 1.

¡¡¡¡The downing of the Black Hawk was the second similar incident in less than a week.

¡¡¡¡On Sunday, a US Chinook transport helicopter crashed in Fallujah after it was hit by what the eyewitnesses said a surface-to-air missile, killing 16 soldiers and wounding 26 others.

¡¡¡¡The pair of attacks raised concern over the thousands of shoulder-launched missiles and numerous RPGs still unaccounted for in the wake of the downfall of Saddam Hussein's regime.

¡¡¡¡Tikrit, 170 km north of Baghdad, and Fallujah, 50 km west of thecapital, are both located within a vast area dubbed as the "Sunni Triangle" where anti-US sentiment was the strongest.

¡¡¡¡After Friday's crash, US troops launched massive raids around Tikrit, searching for suspected assailants.

¡¡¡¡While insisting Saddam himself might not be directly behind these attacks, US administrator in Iraq Paul Bremer said the former regime loyalists and a number of foreign militants were to be blamed. Enditem