BAGHDAD, Iraq – Terrorists attacked British troops at a checkpoint in central Iraq yesterday, killing three and wounding eight in a suicide-bomb and mortar barrage aimed at soldiers sent to the high-risk area to free American forces for an assault on the terrorist stronghold Fallujah.

American troops pounded Fallujah with air strikes and artillery fire, softening up terrorists ahead of the expected assault. Loudspeakers at Fallujah mosques blared out Koranic verses and shouts of “Allahu akbar,” or “God is great,” during the assault, residents said.

The three British soldiers were from the Black Watch regiment, which was moved last month from relatively quiet southern Iraq to the dangerous area just south of Baghdad. An Iraqi interpreter also was killed in the attack, British officials said. Britain’s armed forces minister, Adam Ingram, said in London that the attack was carried out by a suicide bomber in a vehicle and that the British checkpoint also came under mortar fire.

A suicide car bomber also targeted an American Marine convoy near Ramadi, 70 miles west of Baghdad, but only the attacker died in the explosion, American officials said.

Prime Minister Blair agreed to an American request to move British troops to central Iraq despite considerable opposition at home, even within his Labour Party. Scottish Nationalist Party spokesman Angus Robertson warned that the deaths would have “profound implications” for public opinion in Scotland, where the Black Watch regiment is recruited.

American and Iraqi officials want to clear terrorists from Fallujah and other Sunni Muslim areas north and west of Baghdad so elections can be held by the end of January. American officials plan to use a mixed American and Iraqi force to storm Fallujah,40 miles west of Baghdad, if interim Prime Minister Allawi gives the go-ahead.

American aircraft were in action over Fallujah early yesterday, blasting terrorist positions in northeastern and southeastern parts of the city, the military said. American batteries later fired two to three dozen heavy artillery shells at insurgent positions, the military said.

Terrorists and American forces also clashed briefly in Ramadi, but no American casualties were reported.

An Iraqi known for cooperating with Americans was killed near Ramadi, police said. The assailants stopped a car carrying Sheik Bezei Ftaykhan, ordered the driver to leave, and pumped about 30 bullets into his body, police said.

The deteriorating security situation prompted the humanitarian organization Medecins Sans Frontieres, or Doctors Without Borders, to announce it was closing its operations in Iraq. CARE International withdrew from the country after its national director, Margaret Hassan, was kidnapped last month.

American officials say contacts are still under way for a peaceful solution to the crisis in Fallujah, which worsened after Marines abandoned their three-week siege of the city last April, enabling Islamic terrorists to take control there.

In preparation for the planned offensive, Iraqi authorities have put together a team of Iraqi administrators to run the city after the fighting, Marine Major Jim West said yesterday.

Major West said $75 million has been earmarked to repair the city. The strategy is similar to one used when American troops restored government authority in the Shiite holy city Nafaj last August after weeks of fighting with terrorists.