BAGHDAD (AFP) -US and Iraqi forces have launched a major offensive near the Syrian border aimed at destroying an Al-Qaeda stronghold and preventing foreign fighters from entering the country.

Dubbed Operation Steel Curtain, the sweep Saturday involves some 3,500 troops and is the first time several battalion-sized units of Iraq”s armed forces have been involved in joint operations with the US military.

The United States has long held that the most serious terrorist acts in Iraq are carried out by foreign Al-Qaeda operatives, most of whom, it says, cross from Syria via the Euphrates valley.

The area along the 600-kilometer (370-mile) border with Syria is renowned for illegal trade, with cross-border smuggling a way of life for many of the local tribes.

The objective &#34is to restore security along the Iraqi-Syrian border and destroy the Al-Qaeda in Iraq terrorist network operating throughout Husaybah, located on the Iraqi-Syrian border,&#34 the military said.

The operation involves some 1,000 Iraqi army soldiers as well as 2,500 Marines, sailors and soldiers.

Steel Curtain follows two earlier operations, Iron Fist and River Gate, also along the Euphrates valley in the restive western Sunni Arab province of Al-Anbar.

The operation &#34is the largest concentration of Iraqi Army forces to take part in an operation in Al-Anbar this year,&#34 the military said.

The smuggling routes are also open to foreign insurgents, mainly from other Arab countries, albeit crossing in small numbers, Marine Colonel Stephen Davis told AFP earlier.

&#34They do not bring battalions, they bring the leadership, the financial man, the demolition expert,&#34 he said.

Davis said the Marines patrolling the border &#34have intercepted mass ammunition supplies&#34 and even anti-aircraft weapons.

US authorities have repeatedly accused Syrian authorities of allowing rebels, including those associated with Abu Musab al-Zarqawi”s Al-Qaeda group in Iraq, of using their territory as a staging post and a safe haven. Damascus denies the charges.

Syrian authorities reported in late October several clashes between security forces and &#34terrorists&#34 in June and July, with the authorities saying 1,400 militants of different nationalities had been arrested and returned to their home countries.

Meanwhile the US military announced three US soldiers were killed in separate incidents across Iraq on Friday.

The deaths bring to 2,042 the number of US military personnel who have died in Iraq since the March 2003 invasion, according to the Iraq Coalition Casualties, an independent group that follows casualties in Iraq.

The US military on Friday identified five people they said were leaders of Al-Qaeda in Iraq, all killed in an October 29 air strike in Husbayah.

The five dead include four cell leaders and Abu Raghad, described as &#34a North African terrorist&#34 who was &#34the senior (Al-Qaeda) foreign fighter facilitator in the Al-Qaim region and an associate of Zarqawi.&#34

Raghad &#34had contacts throughout the Middle East who were involved in the recruiting, transportation, training and smuggling of foreign fighters and suicide bombers into Iraq,&#34 the military said.

At the United Nations an auditing board has recommended the Washington pay as much as 208 million dollars to Iraq for overbilling or shoddy work performed by a subsidiary of US oil services firm Halliburton, The New York Times reported Saturday.

The work, carried out by Kellogg, Brown and Root, was paid for with Iraqi oil revenues but was delivered at inflated prices or done poorly, the board said, according to the US newspaper.

London”s former ambassador to Washington, Sir Christopher Meyer, said in an interview with the Guardian newspaper that Britain”s involvement in the Iraq war has &#34partly radicalised and fuelled&#34 the rise of home-grown terrorism.

Prime Minister Tony Blair has repeatedly denied that the US and British invasion of Iraq in March 2003 has led to an increase in Islamic extremism and that it played a part in the July 7 attacks in London which left 56 dead.

But former US secretary of state Henry Kissinger warned at a meeting in Brussels with NATO top brass, including US General James Jones and Secretary General Jaap de Hoop Scheffer, against any rushed withdrawal of US forces from Iraq.

&#34American abdication in Iraq will have global consequences if a fundamentalist radical state were to emerge in Baghdad,&#34 Kissinger said, as he called on Europeans to overcome their differences and coordinate efforts to bring stability to Iraq.