An Iraqi holds his mother after she suffered a panic attack following the questioning and near-detainment of her son by US Army soldiers from the 5-20 Infantry Division during the launch of Operation Arrowhead Strike Six in the Shaab neighbourhood of northern Baghdad. Iraqi and US forces swept through a notorious Sunni district of Baghdad, searching houses and seizing weapons in a blitz by around 2,000 US troops and an Iraqi army brigade, a US officer said.(AFP/David Furst)

Tue Feb 6, 5:28 PM ET

BAGHDAD (AFP) - Iraqi and US forces swept through a notorious Sunni district of Baghdad, searching houses and seizing weapons in a blitz by around 2,000 US troops and an Iraqi army brigade, a US officer said.

The capital was already on edge after gunmen dressed in Iraqi army uniforms kidnapped a senior Iranian diplomat following a firefight with his guards, in an attack branded a "terrorist" act by Tehran.

Major Robie Parke of 3-2 Stryker Brigade Combat Team said the security sweep targetted a Sunni district in northeastern Baghdad in the start of a much-vaunted crackdown by US and Iraqi forces on militias and insurgents behind bitter sectarian killings in the capital.

"Iraqi and US forces conducted clearing operations in Adhamiyah today, which is the beginning of the new security plan," Parke told AFP.

Parke said close to 2,000 US troops were involved in the operation, along with the 1st Brigade of the 9th Iraqi Army Division.

An AFP photographer embedded with the US brigade said soldiers searched dozens of houses and that "a large number of weapons were seized and more than a dozen people detained."

Operation Arrowhead Strike Six, one part of a plan expected to involve up to 85,000 US and Iraqi troops, focused on the Shaab and Ur sub-districts.

An aide to Prime Minister Nuri al-Maliki who asked to remain anonymous, denied the operation was the start of the security crackdown.

"The new security plan has not been launched, this is an operation to put pressure on Adhamiyah after we received information that fighters were gathering there," the source said.

The Baghdad plan, announced by US
President George W. Bush along with a decision to deploy another 21,500 US combat troops in
Iraq, aims to clear bastions held by Sunni insurgents and Shiite militias that have killed tens of thousands in the past year.

A high-ranking US army official stressed that the Baghdad security plan was a process involving a broad range of troop movements along with logistics and strategic planning.

"The process has already begun. The Baghdad security plan is a process, its a long operation, it's not going to be a three day operation or a three week operation," the officer said.

"You have to look at the whole process instead of just thinking in terms of a raid, or an operation in one of the districts, it's much, much larger than that."

The official explained that the security operation comprised many steps, many of which had already taken place and each of which contributed to the overall plan.

"That's why you can't say its going to start on 'this day,'.

"There's not a set date."

More US troops have been arriving in Baghdad for at least three weeks while Iraqi forces have also built up in the capital, establishing reinforced security posts at several points in eastern districts on Monday.

"You see it, you see the Stryker brigade here, you see the additional troops coming into Baghdad, coming into Camp Victory and the logistics being established," the officer said.

"You see the increase in the Iraqi army troops that are coming in, a huge huge difference in the Iraqi army, all of that is the process and all of it combined makes the Baghdad security plan."

US Defence Secretary Robert Gates said Tuesday the Bush administration hoped the plan would succeed but was considering alternatives for the troops if it failed.

"We clearly are hoping it will succeed, planning for it to succeed, allocating the resources for it to succeed," he told the
Senate Armed Services Committee.

"But I would tell you that I think I would be irresponsible if I weren't thinking about what the alternatives might be if that didn't happen," he added.

The chronic violence struck an envoy of neighbouring
Iran Sunday, when Jalal Sharafi, the second secretary at Tehran's embassy in Baghdad, was abducted.

"There was a fight between the gunmen who were in Iraqi army uniforms and the Iranian second secretary's guards in central Karrada," a senior Iraqi official told AFP on condition of anonymity.

"After the clashes, the gunmen escaped, taking Sharafi with them."

Iran said the gunmen had links to the Sunni-controlled Iraqi defence ministry and also held the United States responsible.

Sharafi "was abducted on Sunday by a group linked to the defence ministry, which operates under the supervision of US forces in Iraq," foreign ministry spokesman Mohammad Ali Hosseini charged.

The US military rejected Tehran's accusations.

Meanwhile, 28 people died on Tuesday and 30 more corpses were found in Baghdad, while the US military reported deaths of two more servicemembers.