AMMAN, Jordan — Iraq’s prime minister said today that talks with America on a long-term security agreement between the two nations have reached a dead end, saying the American proposals “violate Iraqi sovereignty.”

Prime Minister al-Maliki said the talks slumped because each side refused the other’s demands.

The initial framework agreed upon was to have been an accord “between two completely sovereign states, Mr. al-Maliki said.

The American demands “violate Iraqi sovereignty. At the end, we reached a dead end,” he said.

The prime minister, who spoke to reporters during a visit to neighboring Jordan, said of the American demands that “this is not acceptable.”

Washington and Baghdad have been negotiating behind closed doors a deal that would give American troops legal grounds for an extended stay in Iraq after a U.N. mandate expires December 31.

The talks are also meant to fine-tune a separate accord on political, economic, and cultural ties between the two countries.

But Mr. al-Maliki’s remarks today were the most outspoken and critical comments yet from the Iraqi side, reflecting deep misgivings about the deal, which also has been denounced by Tehran. The Iraqi premier, a Shiite, is close to the predominantly Shiite Iran.

The American Embassy in Baghdad did not immediately respond to a request for comment on Mr. al-Maliki’s remarks.

“I had not heard that,” Defense Secretary Gates said at Brussels, Belgium. “I’m not quite sure what the exact circumstances are, so I will have to when I get home find out what the status of the negotiations is.”

Officials traveling with Mr. al-Maliki tried to soften the impact of his remarks.

A senior al-Maliki adviser, Yassin Majid, said at Amman that despite the “impasse,” negotiations were “still continuing” in a bid to overcome the deadlock.

What was rejected was the “preliminary draft” presented by both sides, “but there are alternative ideas that will be presented to the negotiating table at an upcoming meeting,” he said.

He declined to say when the meeting was to take place, but other Iraqi officials accompanying the prime minister said the impasse came about “because the ceiling of American requests were extremely high.”

The officials, speaking on condition of anonymity because of the sensitivity of the matter, said the main point of contention was the issue of the continued American troop presence in Iraq.

Failure to strike the security deal soon would leave the future of the American military presence in Iraq to the next administration. Mr. al-Maliki’s stance increased doubts the deal could be struck before the upcoming American presidential election.

Iraqi opposition to the deal has mainly focused on concerns that the agreement would cement American military, political, and economic domination of Iraq.

American officials have refused to release details of the talks while they are still under way but have expressed their respect for Iraqi sovereignty.

The top State Department adviser on Iraq, David Satterfield, told reporters this week that the two sides would meet a July target date to finish the agreement, which must be ratified by the Iraqi parliament.

President Bush said this week in Germany that he was also confident that a deal would be reached.