U.S. forces in northern Iraq received 40 nearly combat-ready vehicles Wednesday in a shipment via Turkey, despite Turkish insistence that the U.S. military cannot use its territory as a supply corridor for weapons.

A convoy carried food, fuel and medicine for U.S. troops -- items approved in a hard-won agreement between Washington and Ankara. It was the first significant transit of military equipment through neighboring Turkey since the war started.

But the convoy also carried 40 pickup truck-style Defender 110 Land Rovers, which had poles in the open rear carriage that apparently could serve as machine gun mounts. No weapons were seen in the shipment.

The small U.S. force in Kurdish northern Iraq -- about 1,200 paratroopers and other special forces units -- currently have Humvees fitted with heavy machine guns as its main fighting vehicles.

Turkish officials declined to comment on the convoy. The drivers said they began in Adana, Turkey, which is near the Incirlik air base used by warplanes patrolling the "no-fly" zone to protect Kurds since after the 1991 Gulf War.

Establishing a supply corridor from Turkey could be essential if U.S. commanders decide to strike from the Western-protected Kurdish areas as troops press toward Baghdad from the south. The Pentagon was forced to redraw war plans last month after the Turkish parliament refused to allow 60,000 U.S. troops into Turkey to open a northern front on Iraq.

Also Wednesday, warplanes from the USS Theodore Roosevelt flew about 60 combat missions over northern Iraq, striking artillery, air defenses and troop bunkers, said officers on board.

A statement attributed to Saddam Hussein and read Wednesday on Iraqi state television warned Kurdish leaders against cooperating with U.S. forces: "I advise you not to rush and do something that you'll regret so long as you know that this leadership and the government it leads in the face of invaders will remain."

The United States, which has protected the Kurds' autonomous region with air patrols since 1991, has begun working with the Kurds' 70,000 soldiers in their joint aim of overthrowing Saddam.

Iraq staged its first concentrated artillery assault on the Kurds in the autonomous north Wednesday, shelling the town of Kifrey a day after mortar and missile attacks there killed three civilians and wounded a dozen others.

Kifrey sits at a strategic crossroads leading to the oil center Kirkuk, to Saddam's hometown and power base Tikrit, and to Baghdad, less than 100 miles to the south.

Officials in the Patriotic Union of Kurdistan, the Kurdish party that controls the area, say the Iraqis have bolstered their position with several tanks at the Kifrey front. A large concentration of Iraqi troops is reported based at Jelola, south of Kifrey -- a likely target of coalition planes.

With the U.S. offensive reaching the doorstep of Iraq's capital, the northern coalition of Kurdish fighters and American military oversight may be nearing a decisive moment. Some Kurdish commanders believe the coming days will tell whether an offensive will be needed.

"What happens in Baghdad will decide what happens in the north," said Ares Abdullah, who controls a front line Kurdish unit in the Taqtaq region southwest of Irbil, the administrative capital of the Kurdish zone. A withdrawal by Iraqi forces last week allowed his militiamen to move within 18 miles of the key oil center of Kirkuk.

Kirkuk and Mosul would likely be the main objectives of a northern push to try to unravel Saddam's forces. Kurds consider both areas part of their historical ethnic territory.

U.S. Marine Maj. Gen. Henry P. Osman met Wednesday with Kurdish leaders Jalal Talabani and Massoud Barzani in the resort town of Dukan. There were no statements after the talks.

Air strikes against Iraqi targets in the north have shifted to forward positions in recent days, adding to speculation that some type of northern attack was planned. So far, the clearest result has been an Iraqi withdrawal toward Kirkuk on several fronts.