U.S. fighter planes in Iraq have begun dropping bombs on insurgent targets in western Iraq as part of a major combat operation launched against Iraqi rebels.

Military officials say about 1,000 troops are taking part in "Operation Spear," which began early Friday in Iraq's restive Anbar province, near the Syrian border.

Reuters news agency says U.S. fighter planes have dropped at least nine 220-kilogram bombs on insurgent target areas near the town of Qaim. Casualty figures are not yet available.

Anbar province is where U.S. forces say they killed about 40 militants in air strikes in Karabila on June 11.

Elsewhere, at least six Iraqi police were killed and more than 20 others wounded Thursday in a suicide car bombing on Baghdad's airport road. And an Iraqi judge and his driver were gunned down in the northern city of Mosul.

Some information for this report provided by AP and Reuters.