BAGHDAD, Iraq (AP) – An American helicopter was shot down and crashed north of Baghdad on Wednesday, the military said after initially stating that the chopper made a “hard landing.” All aboard were safely evacuated by a second helicopter.

At least seven American helicopters have crashed or been forced down under hostile fire since Jan. 20. Military officials have said that militants are increasingly targeting helicopters amid the buildup of American troops in Baghdad, firing simultaneously with an assortment of weapons from different directions.

The military has also detected another deadly insurgent tactic in recent weeks – the spreading of toxic chlorine gas by combining it with explosives.

In Washington, two Pentagon officials said the tactic has been used at least three times since Jan. 28, when a truck carrying explosives and a chlorine tank blew up in Anbar province west of Baghdad. More than a dozen people were reported killed.

On Tuesday, a tanker filled with chlorine exploded and noxious plumes covered homes and schools north of Baghdad. Nine people were killed and 150 people were wounded, said one of the officials. A day later, a pickup truck exploded near a diesel fuel station in southwestern Baghdad, the official said.

A third defense official said America has been concerned about militants’ ability to acquire weapons like chlorine bombs. But so far, the official said, bomb makers in Iraq haven’t been able to disperse a chemical such as chlorine in an effective way. Meanwhile, Britain outlined its plan to withdraw around 1,600 troops from Iraq in the coming months and Denmark said it will withdraw its 460-member contingent by August. Lithuania also said it may pull back its 53 troops from the country.

Secretary of State Rice said that despite the announced withdrawals, “the coalition remains intact.” In Japan, Vice President Cheney said America wants to finish its mission in Iraq, then “come home with honor.”

Political tremors also grew stronger in Iraq following claims that a Sunni woman was raped while in custody of the Shiite-dominated police – a case that threatens to escalate the sectarian friction that drives many of the bombings and attacks across the country.

Prime Minister Nouri al-Maliki fired the head of the influential Sunni Endowment, who had called for an international investigation into the rape allegations.

In the latest violence, a suicide car bomber struck a police checkpoint in the Shiite holy city of Najaf, killing 13 people in the spiritual heartland of the militia factions led by radical cleric Muqtada al-Sadr.

The blast hit while streets were filled with morning shoppers. At least seven of the victims were police and the rest civilians, authorities said. It was the first large-scale bombing in months in the city, which is heavily guarded by police and Mr. al-Sadr’s powerful Mahdi Army militia. More than 40 people were injured.

On Aug. 10, a suicide attack near the Imam Ali mosque killed at least 35 people and wounded more than 100.

Government officials marked the first week of a wide-ranging security sweep in Baghdad by American and Iraqi forces seeking to put death squads and insurgents on the run. But a string of bombings in the Baghdad area – which have claimed more than 100 lives since Sunday – have quieted the early fanfare and highlighted the huge challenges of trying to reclaim control of the blood-soaked capital. The Iraqi spokesman for the security plan, Brigadier General Qassim Moussawi, said the campaign to reclaim control of the city neighborhood by neighborhood “has achieved very important goals despite the expected criminal reactions.”
“God willing, the plan will continue to uproot terrorists and outlaws across Baghdad and other areas,” he told a news conference. He added that 42 “terrorists” have been killed in the sweeps and more than 250 suspected militants arrested, but gave further details.

Gemeral Caldwell told a news conference that American and Iraqi forces were focusing on “belts” of extremist activity in Baghdad and suggested political talks are continuing over when and how to move into Sadr City, a stronghold of the Mahdi Army militia.
<[>He added that American military planners are moving ahead with efforts to establish smaller outposts around Iraq. They seek to work with Iraqi soldiers on forging ties with community leaders and gathering sharper intelligence on militants.

“If we are going to protect the population, we have to be down there with the population,” he said.

In London, British Prime Minister Tony Blair said about 1,600 British troops will leave Iraq in the coming months if Iraqi forces can secure the southern part of the country. Britain – the main coalition ally in Iraq – has about 7,100 soldiers in Iraq, concentrated in and around the southern city of Basra

British troops will stay in Iraq until at least 2008 and work to secure the Iran-Iraq border and maintain supply routes to American and coalition troops in central Iraq, Blair told the House of Commons.

Ms. Rice played down the British announcement, saying it is consistent with the American plan to turn over more control to Iraqi forces when possible.

“The British have done what is really the plan for the country as a whole, which is to transfer security responsibility to the Iraqis as the situation permits,” Rice said in Germany. “The coalition remains intact and, in fact, the British still have thousands of troops deployed in Iraq.”

Elsewhere in Iraq, an American Marine was killed Tuesday in fighting in volatile Anbar province, the military said.

At least 3,149 members of the American military have died since the war began in 2003, according to an Associated Press count.
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Associated Press writers Pauline Jelinek and Katherine Shrader in Washington contributed to this report.