Iraq is "not going to be pushed around" by Iran, the top U.S. diplomat in Iraq said Saturday following an Iranian takeover of an oil well along the two nations' disputed border.

U.S. officials said they approved of Iraq's speedy defense of its sovereignty amid ongoing concerns over Iran's influence on its Mideast neighbor.

"It does speak to the overall view here that they are not going to be pushed around by Iran," U.S. Ambassador to Iraq Chris Hill told reporters.

Iranian forces earlier this week crossed into Iraq, seizing an oil well just over the border in the southern Maysan province. The takeover — which included planting an Iranian flag on the well — was met by protests from Baghdad.

It served as a dramatic display of the sometimes tense relations between the wary allies.

Iraqi authorities on Saturday prevented media representatives from visiting the area at the al-Fakkah oil field, located about 200 miles southeast of Baghdad.

Top Iraqi national security officials said the well was clearly in Iraqi territory and demanded that the Iranians leave immediately.

High-level diplomatic talks between Iraq and Iran are continuing, said Iraqi deputy foreign minister Labid Abbawi.

"The situation this morning is the same: the Iranians have not withdrawn from the well," Abbawi told The Associated Press. "We are still sticking to our position in demanding an immediate withdrawal of Iranian forces from the oil well."

Iranian Foreign Ministry spokesman Rahmin Mehmanparast denied that Tehran had seized the oil well and sought only to reduce tensions between the neighbors, accusing foreign media of spreading false news to "disrupt good relations" between Tehran and Baghdad.

"Diplomatic and technical mechanisms" were the way to deal with the issue, said Hasan Kazemi Qomi, the ambassador to Iraq, according to the semiofficial Fars news agency.

Army Gen. Ray Odierno, commander of U.S. forces in Iraq, told reporters that the Iranian forces had withdrawn from the oil well as of Saturday morning. But an oil worker at the field said five Iranians remain inside the well, and the Iranian flag still flew above it.

The worker, who did not want to be identified for fear of retribution, said Iranian troops were watching the well from a hillside on Iran's side of the border.

An Iraqi Interior Ministry official, meanwhile, said Iraqi troops and border guards have moved to a staging ground about a kilometer from the well, awaiting orders. The official, who was at the scene, was not authorized to discuss the situation with the media and spoke on condition of anonymity.

It was not clear as well what kind of Iranian forces had been at the well. An Iraqi official and an eyewitness described them as soldiers. The Iraqi government spokesman described them only as an armed Iranians.

Earlier Saturday, the top American military official said the oil well takeover appeared to be the latest example of Iran flexing its influence over Iraq and other Mideast nations. However, Joint Chiefs Chairman Adm. Mike Mullen called it an issue for the Iraqi government to settle, and said there were no plans by the United States to intervene.

Once bitter enemies, Iraq and Iran settled into a more positive, if still uneasy, relationship after a Shiite-led government came to power following the 2003 U.S.-led invasion.

"I continue to worry about the influence of Iran," Mullen, in Iraq for a two-day visit with U.S. and Iraqi authorities, said at a news conference in Baghdad. "I still think it's important that Iran have a constructive, positive influence in this region and globally. And there are just too many examples where that is not the case."

Odierno also said Iran continues to fund and train fighters in Iraq, as well as send weapons and equipment over the border — although less frequently now than in the past.

Analysts said it was too early to say whether the incident would mushroom into greater tension but said it could raise concerns with oil companies looking to invest in Iraq.

Oil prices rose slightly after news of the incident.