BAGHDAD — New American proposals have failed to overcome Iraqi opposition to a proposed security pact, two lawmakers said yesterday, and a senior government official expressed doubt an agreement could be reached before the American presidential election in November.

Iraqi reinforcements, meanwhile, arrived in the oil-producing southern city of Amarah yesterday as the military geared up for another crackdown against Shiite militia fighters, officials said.

The security agreement would provide a legal basis for the presence of American forces in Iraq after the U.N. mandate expires at the end of this year. Failure to strike a deal would leave the future of the American military presence here to the next administration.

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

A Shiite member of the parliamentary committee on legal affairs, Iman al-Asadi, said the latest American version “wasn’t satisfactory to say the least.”

She said the American proposals contained “some good points but they were not up to what we had expected.” Mr. Asadi said the committee had recommended to the negotiators that they reject the latest draft, the fourth since the talks began last March.

A Kurdish lawmaker, Mahmoud Othman, confirmed Mr. Asadi’s comments, adding that “we will not sign” the agreement as proposed by Washington.

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 told reporters this week in Germany that he was also confident that a deal would be reached.

But a senior Iraqi official told the Associated Press that the chance of finalizing an agreement before the American presidential election was “slim,” although he added that Prime Minister al-Maliki’s government was interested in a deal if it served Iraqi interests.