Iraq acknowledged Friday it has barred U.N. weapons inspectors from two more sites suspected of holding banned weapons material, raising to five the number of bases declared off-limits since Tuesday.

Deputy Prime Minister Tariq Aziz said inspectors were barred because of "national security considerations" and said they were suspected of spying. He also accused the chief inspector, Rolf Ekeus, of trying to whip up anti-Iraq sentiment at the United Nations.The weapons inspectors, working in shifts around the clock, maintained a barricade at the exits of one of the five sites today, the fourth day of the standoff between Iraq and the United Nations. All five installations belong to President Saddam Hussein's elite Republican Guard.

Iraq must dismantle all its weapons of mass destruction before the U.N. Security Council will consider lifting sanctions imposed after the August 1990 invasion of Kuwait that led to the Persian Gulf War.

Ekeus heads the U.N. Special Commission, which was formed in 1991 to oversee the elimination of Iraq's ballistic missiles, chemical and biological arsenals and nuclear weapons program.

Ekeus said in New York on Thursday that there was "a high probability that Iraq is hiding items" in the bases.

The inspectors have had repeated confrontations with Iraqi officials over access to sites since their mission began five years ago. Aziz blamed the latest standoff on Ekeus.

"It is noticeable that (Ekeus) is concentrating on sites other than those we have always allowed the inspectors to visit," Aziz said. "This is an intentional move to increase tensions."

Aziz also referred to a Security Council demand Wednesday for immediate, unconditional access to all sites the weapons team wants to see and a call by the United States and Britain for a tough response to Iraq's defiance.

"Every time the chairman creates tension, we find the United States and Britain already have a new resolution ready. This points to some collaboration among the three sides," Aziz said.