The top U.S. military officer quizzed Iraqi leaders Friday about the influence and motives of next-door Iran as national elections approach, but made no promises when his hosts asked for surveillance equipment and other help to keep an eye on their neighbors.

Hours before Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, visited the southern Iraqi city of Basra, near the Iranian border, Iranian troops crossed into Iraqi territory and seized an oil well in a disputed area along the border, Iraq's deputy foreign minister said.

Such incidents have happened before along the border, which was never clearly delineated after the extended war between the two countries in the 1980s.

Mullen was not specific in his comments, but the United States accuses Iran of training, arming and financing Shiite militias like the one in Basra that was the target of a fierce military crackdown last year.

U.S. and Iraqi leaders are watching for signs that Iran is trying to meddle in the upcoming Iraqi elections, and keeping tabs on what they describe as an Iranian goodwill campaign in southern Iraq.

Mullen also emphasized throughout a day of meetings in Iraq that the U.S. will stick to its plan to rapidly withdraw forces beginning almost immediately after the election on March 7.

"That draw down from 115,000 to 50,000 is going to happen, no doubt in my mind," Mullen told a group of enlisted men and women at a U.S. base in Basra.

The election was postponed from January, but Mullen said that will not change U.S. plans.

A Shiite cleric, Abdul Aziz Moosawi, greeted Mullen warmly and told the American he was grateful for U.S. help despite earlier skepticism.

Mullen asked the cleric and a senior Iraqi Army general for their views on Iranian influence and how they see Iran in the future, "because Iran worries me a great deal."

The cleric bluntly explained the calculus of life next door to powerful and influential Iran.

Iran's influence is inevitable and sometimes works in positive ways, Moosawi said. "But I think we feel the negative impact more," he said.

Western and Arab analysts long had feared that a Shiite-governed Iraq inevitably would fall under the sway of its far larger Shiite neighbor, enabling the Iranians to expand their influence westward into a crucial Arab country in the Middle East.

Iran and Iraq maintain close commercial and cultural ties, from Iranian consumer goods in the markets of Basra and Najaf in southern Iraq to the tens of thousands of Iranian pilgrims who visit Shiite religious sites here every year.

But Iran appeared to be the loser in separate regional elections in Iraq last year, in which Iranian-linked candidates did poorly.

Suspicion of Iran and an undertone of Iraqi nationalism surfaced in Mullen's discussions in Basra and Talil.

"Iran is trying to dominate not only in Basra ... Iran is trying to dominate in many provinces in southern Iran," Maj. Gen. Aziz Swady told Mullen.

In Talil, several speakers invited to a discussion session with Mullen asked for help protecting the border with Iran. Iran is trying to meddle in the election, Mullen was told. Iraqis asked for equipment such as monitoring towers and high-tech surveillance gear. Mullen did not commit.