Doubts over America's northern pincer may give Saddam a chance to strengthen his defences

The failure of America to persuade Turkey to allow its bases to be used by troops for an attack on Iraq has complicated Washington's plans to open a northern front against Saddam Hussein.

The United States had hoped to attack Iraq from the north and south. Now the existence of the northern pincer is in doubt. About 62,000 US soldiers and 310 military aircraft were to be deployed in Turkey, enabling the 4th Infantry Division to push south. The prizes in the great plain stretching north from Baghdad are the cities of Mosul and Kirkuk. The capture of Mosul, the second largest city in Iraq, would be a serious blow to the Iraqi government because it is the home of many army officers and officials. Kirkuk is, if anything, more essential. The province is a main producer of oil. America fears that if its attack is delayed President Saddam might use the time to blow up the oilfields, as he did in Kuwait in 1991.

Securing Kirkuk swiftly was also considered important by policy makers because of its political value. The Kurds consider Kirkuk to be a Kurdish city from which they have been ethnically cleansed under President Saddam's campaign of "Arabisation".

Washington has claimed that it can redeploy its troops destined for the north to the southern front but this would allow President Saddam to withdraw troops from around Kirkuk and Mosul. A central American purpose was to pin down these Iraqi soldiers. The Iraqi army has 12 divisions defending the two cities. Each is supplemented with one Republican Guard division and local militia called the al-Quds army. If these divisions are up to strength, the Iraqi leader would have at least 120,000 regular soldiers – possibly 180,000 – in the north, according to Karim Sinjari, the Kurdish Interior Minister. Does America have an alternative strategy to take northern Iraq if Turkey does not buckle under pressure? For a full deployment, these facilities are essential. But Washington could base smaller forces in Iraqi Kurdistan.

There are a number of problems. There are airstrips in the region, but none provides the facilities a large force would require. And if American troops used Iraqi Kurdistan as an alternative this would immediately start a war. The area is under the control of the Kurdistan Democratic Party and the Patriotic Union of Kurdistan but it is Iraqi territory.

The Iraqi regular forces are considered weak. Barzan Ismail, the security commander in Arbil, said yesterday that "the Iraqis have thinned out their front line" at the bridge over the Greater Zaab river, west of Arbil.Nevertheless, even these soldiers seem to be on the alert. Mr Ismail said they shot and slightly wounded a foreign journalist who was taking photographs of their positions.

Patrick Cockburn is a visiting fellow at the Centre for Strategic and International Studies in Washington and co-author, with Andrew Cockburn, of 'Saddam Hussein: An American Obsession'