"Troops walked into the DMZ this morning at around 11 a.m. (3 a.m. EST)," a Kuwaiti security force source working in the Umm Qasr area in the east of the zone said. "American convoys are still driving toward Umm Qasr."
Tens of thousands of U.S. and British troops are in the desert in north Kuwait preparing to attack. President Bush has said his forces will invade if Iraqi President Saddam Hussein does not flee by early Thursday.
A U.S. military spokesman said he could not confirm or deny that troops were inside the DMZ. A British army spokesman said only that soldiers had taken up "forward battle positions."
The DMZ extends three miles into Kuwait and six miles into Iraq. It was not clear how far in the troops were. United Nations observers pulled out of the DMZ on Monday. Small groups of engineers slipped in last week to cut gates in the fence but combat units were now in place there, the sources said.