BAGHDAD, Iraq (AP) _ Economic sanctions cannot be eased until Iraq turns over a complete list of the foreign companies that contributed to its arsenal, the chief U.N. nuclear inspector said Sunday.

Maurizio Zifferero, head of a team that left Baghdad for Bahrain on Sunday, also said that without long-term monitoring, there was no way to ensure Iraq will not again seek to develop a nuclear weapon.

Iraq has so far rejected such monitoring.

The U.N. cease-fire resolutions that ended the Persian Gulf War require Iraq to surrender its chemical and nuclear weapons. U.N. inspectors are trying to root out such weapons and oversee their destruction.

Zifferero, deputy head of the International Atomic Energy Agency, told reporters a complete list of the foreign companies that helped Iraq build its nuclear weapons program was necessary to develop a full picture of the program.

He said the Iraqis were aware that failure to provide such a list ''is a stumbling block'' to lifting sanctions. ''We cannot concede to give them a declaration of compliance without our being fully satisfied on the procurement items,'' he said.

He added that ''I can't see any way'' of lifting or easing U.N. sanctions until such a list if provided.

For months Iraq has refused to provide it, saying it was a matter of protecting confidential, sovereign trade. But recently Iraq agreed to supply answers to specific questions from the inspection team.

Iraq says the United Nations already knows about 90 percent of the names - about 80 companies - and now is willing to discuss the remaining 10 percent.

Zifferero said the past week's inspection was routine and no new sites were visited. He said officials still were working on a long-term monitoring plan which would be phased in.

He said preliminary analysis of water samples indicates there has been no prohibited nuclear activity in Iraq for the past two years.

Though Zifferero's team was leaving Sunday, a 4-man ballistics team remains in Baghdad to conduct daily inspections of a major missile center outside the capital. Also, an aerial inspection team continues work and a chemical weapons destruction team is eliminating stockpiles of mustard gas and nerve agent.