DHAHRAN, SAUDI ARABIA, JAN. 24 -- A CBS television crew headed by chief Middle East correspondent Bob Simon has been missing since Monday after driving through northern Saudi Arabia to the Kuwaiti border, CBS and U.S. military officials said today.

Concerns about the crew increased today after Saudi military officials located a Toyota land cruiser used by the CBS team near the Kuwaiti border. The vehicle was out of gas and the keys were in the ignition, according to CBS colleagues of Simon here.

Saudi trackers followed footprints from the vehicle into Kuwait as far as the first checkpoint manned by Iraqi forces, according to Saudi military officials. Saudi officials investigating the disappearance found $6,000 in cash, Iraqi currency, television equipment and a wristwatch with Iraqi leader Saddam Hussein's face on the dial inside the abandoned vehicle.

Simon was wearing a desert uniform when he left his hotel here, and there was speculation that he and his crew could have been mistaken for military personnel.

"It is our hope that they are with friendly forces," said Tom Goodman, a spokesman for CBS in New York. "However, we do not know at this point and we are doing everything humanly possible to try to locate them."

The missing crew also includes producer and London bureau chief Peter Bluff, cameraman Roberto Alvares and sound man Juan Caldera.

The crew left here on Sunday to prepare a story about the growing military buildup near the border. Convoys of U.S. troops and other coalition forces have been heading north for the past month to prepare for an anticipated ground offensive against Iraqi forces. There have also been sporadic reports of shelling by the Iraqis against U.S. troops.

Simon checked in with CBS producers here late Monday morning from the northern Saudi Arabian town of Hafar al Batin, about 50 miles from the border, but hasn't been heard from since then, colleagues said.

Simon is a veteran foreign correspondent who has covered fighting in Vietnam, Lebanon, Northern Ireland and other areas. "It's not uncharacteristic for him that he would try to go to the border," said one colleague who asked not to be identified. "What is uncharacteristic is that we haven't heard from him."

U.S. military forces "have been alerted" to look for the missing crew, said Navy Cmdr. Eric Willenbrock, a spokesman for the Pentagon's joint information bureau here.

Willenbrock also said the CBS crew had not abided by Pentagon ground rules requiring all coverage of war-related events to be done as part of a media pool of several news organizations accompanied by military escort.

"He went up there on his own," said Willenbrock.

Staff writer Molly Moore contributed to this report from Dhahran.