"It [the attack] was against a multinational force warrior patrol. All of the soldiers were part of the British contingent," he said.
The main blast left a crater in the road at least a metre deep and several metres across.
"We heard two explosions that shook the house. I went out and saw one armoured vehicle that was completely destroyed and another with less damage. I saw some soldiers being taken away, but I don't know how many," one resident said.
The British military denied accusations by Iraqi police that British troops had stormed a police checkpoint close to the scene of the attack shortly afterwards and beaten some officers.
The US military said the four American soldiers were killed by roadside bombs around the Iraqi capital.
"The chances of success [in Iraq] are essentially zero because the Iraqi people have no voice"
Non Sequitur, Cadiz, Spain
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The attacks follow a relatively quiet period in Baghdad, where US and Iraqi forces have deployed thousands more troops in an attempt to bring security to the city.
The US military also said that a helicopter carrying nine people had been downed south of Baghdad on Thursday. Four people were injured.
Witnesses told Reuters news agency that heavy gunfire had forced the aircraft down near Latifiya, 40km from the capital.
Nine US helicopters - including two operated by private security firms - have been downed in Iraq since January 20, most of them as a result of attacks from the ground.
The Iraqi checkpoint in Mosul came under attack from at least 40 armed men, an Iraqi army source said.
Ten soldiers were killed and one injured as their vehicles were set on fire and their weapons seized.
"Apparently the soldiers were asleep when the attack happened. They were taken by surprise and did not have a chance to respond," the source said.
TV station bombing
An Iraqi journalist was killed when a suicide truck bomb was exploded outside the offices of Baghdad TV in the western Al-Jamiyah district of the capital.
|One person was killed when a truck was blown |
up outside the offices of Baghdad TV [AFP]
"The Baghdad TV headquarters was targeted by a cowardly car bomb attack followed by a gun attack, killing deputy bureau chief Thaer Ahmed Jabr," the Iraqi Islamic Party said in a statement.
Another 12 employees of the television channel were wounded, some of them seriously, it added.
The attack came as Nuri al-Maliki, the prime minister, paid tribute to Iraqi journalists killed during the conflict.
"National media outlets that are committed to serve the truth have turned into a spearhead against terrorists who have launched a violent campaign against journalists faithful to their nation and people," a statement from al-Maliki said.