BAGHDAD—New U.S. proposals have failed to overcome Iraqi opposition to a proposed security pact, two lawmakers said Thursday, and a senior government official expressed doubt an agreement could be reached before the U.S. presidential election in November. Iraqi reinforcements, meanwhile, arrived in the oil-producing southern city of Amarah on Thursday as the military geared up for another crackdown against Shiite militia fighters, officials said. The Interior Ministry denied a new offensive was imminent.

The security agreement would provide a legal basis for the presence of U.S. 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.U.S. negotiators offered new proposals this week after Iraqi lawmakers 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.

Iman al-Asadi, a Shiite member of the parliamentary committee on legal affairs, 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.” Al-Asadi said the committee had recommended to the negotiators that they reject the latest draft, the fourth since the talks began last March.