Baghdad ? Iraq’s prime minister told The Associated Press on Friday that a U.S. Senate proposal to split the country into regions according to religious or ethnic divisions would be a “catastrophe.”

The Kurds in three northern Iraqi provinces are running a virtually independent country within Iraq, while nominally maintaining relations with Baghdad. They support a formal division. But both Sunni and Shiite Muslims have reacted with extreme opposition to the U.S. Senate proposal.

The majority Shiites, who would retain control of major oil revenues under a division of the country, oppose the measure because if would diminish the territorial integrity of Iraq, which they now control. Sunnis would control an area with few if any oil resources. Kurds have major oil reserves in their territory.

The nonbinding Senate resolution calls for Iraq to be divided into federal regions under control of the three communities in a power-sharing agreement similar to the one that ended the 1990s war in Bosnia. Democrat presidential hopeful Sen. Joseph Biden was a prime sponsor of the measure.

“It is an Iraqi affair dealing with Iraqis,” Prime Minister Nouri al-Maliki told AP on a return flight to Baghdad from New York where he appeared at the U.N. General Assembly. “Iraqis are eager for Iraq’s unity. … Dividing Iraq is a problem, and a decision like that would be a catastrophe.”

The comments were al-Maliki’s first since the measure passed the Senate on Wednesday.

Iraq’s constitution lays down a federal system, allowing Shiites in the south, Kurds in the north and Sunnis in the center and west of the country to set up regions with considerable autonomous powers.

Nevertheless, ethnic and sectarian turmoil have snarled hopes of negotiating such measures, especially given deep divisions on sharing the country’s vast oil resources. Oil reserves and existing fields would fall mainly into the hands of Kurds and Shiites if such a division were to occur.

So far there has been no agreement on a broader sharing of those revenues, one of the several U.S.-mandated benchmarks the government has failed to push through parliament.

On Thursday, Iraqi Vice President Adel Abdul-Mahdi, a Shiite, said decisions about Iraq must remain in the hands of its citizens. And a spokesman for radical Shiite cleric Muqtada al-Sadr demanded the al-Maliki government reject the proposal.

“We demand the Iraqi government to stand against such a project and to condemn it officially,” said Liwa Semeism, the al-Sadr spokesman. “Such a decision does not represent the aspirations of all Iraqi people and it is considered an interference in Iraq’s internal affairs.”