Iraqi troops moved into new positions around President Saddam Hussein's hometown Thursday, and South African disarmament experts visiting Iraq appealed to the U.N. Security Council to give weapons inspections more time.

U.N. inspectors, meanwhile, found some fragments of biological weapons bombs Iraq says it destroyed in 1991 at an airfield near the town of al-Aziziya.

With tensions rising, two U.S. defense officials said on condition of anonymity that American intelligence had detected Saddam moving some elite army troops into new positions around his hometown of Tikrit, 100 miles north of Baghdad.

Travelers on Thursday saw dozens of tanks being transported by truck from the northern city of Mosul to an area near Tikrit. Both tanks and anti-aircraft guns were dug in at a long string of deep trenches with only their turrets exposed near Tikrit.

Dozens of armored personnel carriers rumbled both ways along the route.

Saddam, his son Qusai, the defense minister and the minister of military industries all met Thursday with soldiers and military researchers, who promised not to let the leadership down, the official Iraqi News Agency said.

In New York, U.N. Security Council members met behind closed doors on Thursday to discuss a proposed U.S.-British-Spanish resolution that could authorize war for failing to disarm.

In a letter to chief U.N. weapons inspector Hans Blix on Thursday, Iraq agreed "in principle" to destroy its Al Samoud 2 missiles, which were found to have a range exceeding the 93-mile limit set by the Security Council at the end of the 1991 Persian Gulf War.

But it wasn't immediately clear whether Iraq's letter constituted an unconditional acceptance and whether Iraq would meet the Saturday deadline to begin the destruction, as Blix has ordered.

Iraq asked Blix to dispatch a technical team to discuss the "framework and timetable" for carrying out the order, but Blix's deputy was already in Baghdad to oversee the destruction.

South African disarmament experts visiting Iraq said Thursday they were convinced Iraq was doing its best to disarm, and appealed to the Security Council to give weapons inspections more time.

"It's clear there is movement on the whole issue of weapons of mass destruction," South Africa's Deputy Foreign Minister Aziz Pahad said at a Baghdad news conference. "Clearly [the inspection regime] is working, and if it's working why stop it?"

"The Iraqi side has consistently told us that every time they move on an issue, the goal post gets changed," Pahad said.

The South African team has been in Baghdad since Sunday night to share its experience in verifiably destroying weapons programs. It was to leave Friday morning.

In the 1990s, U.N. inspectors were sent to South Africa and praised the country's voluntary destruction of weapons of mass destruction during the previous decade.

The inspectors, meanwhile, returned to an airfield near the town of al-Aziziya, 60 miles southeast of Baghdad, where Iraqi workers dug in search fragments of R-400 biological weapons bombs Iraq says it destroyed there in 1991. Hiro Ueki, spokesman for the inspectors, said some fragments were found.

A second team of inspectors supervised workers who drilled holes in eight remaining 155mm artillery shells filled with mustard gas that Iraq reported to the inspectors, Ueki said.

Ueki also confirmed an Iraqi report that French Mirage reconnaissance planes have begun flying in support of the U.N. inspections. Three American U-2 spy planes -- which fly at higher altitudes -- already have made similar runs.