Talks between Iraq and the United States over long-term security arrangements are deadlocked because of U.S. demands that encroach upon Baghdad's sovereignty, the Iraqi Prime Minister Nouri al-Maliki said Friday.

The negotiations are aimed at providing a legal basis for a long-term U.S. troop presence in the country when a United Nations mandate expires on Dec. 31, as well as separate long-term deals on political, economic and security ties between the two countries.

In his strongest comments yet on the debate, al-Maliki echoed concern by Iraqi legislators that the U.S. proposals would give Washington too much political and military leverage over Iraqi affairs.

"The first drafts presented left us at a dead-end and deadlock," he told reporters in Amman, Jordan. "So, we left these first drafts and the negotiations will continue with new ideas until the sides reach a formula that preserves Iraq's sovereignty."

Officials say proposals to entrench powers of arrest for American troops and to give them immunity from prosecution in Iraq are the most controversial measures being discussed.

"One of the important issues that the U.S. is asking for is immunity for its soldiers and those contracting with it. We reject this totally," al-Maliki said.

U.S. hopeful talks will succeed

U.S. negotiators offered new proposals this week after Iraqi legislators expressed outrage over the direction of the negotiations, claiming that accepting the U.S. position would cement American military, political and economic domination of this country.

The U.S. embassy in Baghdad stressed the pact was important for Iraq's security.

"Those discussions are based on the fundamental principle of U.S. recognition of and respect for Iraq's sovereignty," embassy spokeswoman Mirembe Nantongo said.

"We remain hopeful, as do our Iraqi government partners, regarding a successful conclusion to these negotiations," she added in an e-mailed statement to the Associated Press.

The mounting Iraqi criticism has raised doubt that a deal could be reached before the U.S. presidential election in November. The issue also has taken on importance among Iraq's fractured political parties as they prepare for provincial elections expected in the fall.

An aide to Iraq's pre-eminent Shiite cleric, Grand Ayatollah Ali al-Sistani, urged negotiators to protect the national interest during a sermon Friday in the holy city of Karbala.

Democrats also doubtful

"Iraq's sovereignty and economy must be protected," the aide told worshippers.

Democrats in the United States have also expressed unease about the negotiations, fearing that an agreement could lock the next U.S. administration into a long-term troop presence in Iraq that a Democratic administration might want to curtail.

The United States has similar pacts, known as "status of force agreements," with 80 countries.