Iraq's army has voiced concern about U.S.-led allies approaching a key northern city, after Baghdad rejected a United Nations role taking over the allies' job of protecting safe zones for the Kurds, officials say.

The Iraqi actions Thursday could further complicate efforts by President Bush and other allied leaders to turn over control of the safety zone to the world body.But Iraq also has promised not to shoot at allied planes patrolling allied-occupied northern Iraq, and it took a step toward working with the Kurds on Thursday by agreeing to form a joint police force in the secure zone, officials said.

U.S.-led allies are working in the region to pave the way home for Kurdish refugees who fled to the mountains to escape the crushing of a post-gulf war rebellion. The allies on Thursday also shut down a Kurdish guerrilla checkpoint believed to slow the refugees' return.

In other developments:

- Defense Secretary Dick Cheney, touring the Persian Gulf, said Thursday he had won "broad agreement" from Persian Gulf governments on steps to strengthen their defenses and to permanently expand the American military presence in the region.

- The United Nations official in charge of the embargo on Iraq said that nations could release Iraqi assets to allow Baghdad to buy humanitarian supplies. Iraq had asked for $1 billion to be freed.

- Iraq reported 52 cases of cholera in areas close to the Turkish and Iranian borders, both destinations of refugees. While up to 800,000 Kurdish refugees fled toward Turkey, about 1.2 million Shiite Muslim and other Iraqi refugees fled to Iran to escape their own crushed rebellion in southern Iraq.

- Heartened by Kurdish leaders' talks in Baghdad on a homeland and repulsed by filthy refugee camps, more than 70,000 Kurdish refugees who fled to Iran have gone home, relief officials said in Tehran.

The Iraqi army has toughened its position around Dohuk, 25 miles from the Turkish border, placing more than 1,000 soldiers on the hills surrounding the city and bringing units from southern Iraq to camp on highway accesses into the city, allied intelligence officers have said.