Baghdad ? U.S. Ambassador Ryan Crocker on Sunday accused Iran of trying to interfere with a new security pact between Iraq and the United States, and said Americans need to view Iraq with “a sense of strategic patience” because the stakes in the region are so high.

The 37-year veteran diplomat, interviewed by The Associated Press at his embassy in Baghdad, is in the middle of tough negotiations with Iraqi officials to define the basis for a continuing American military presence in the country beyond the end of this year.

The talks hit an impasse recently and are taking place against a backdrop of increasing calls in the United States for a U.S. withdrawal and declining interest in the war itself from many members of the American public.

Crocker struck an emotional note in discussing the recent accomplishments in Iraq, including a sharp decline in violence across much of the country and some preliminary steps toward political reconciliation, such as last week’s agreement to schedule provincial elections by Jan. 31.

“All Americans should be and are proud of the achievements in Iraq and the American role in bringing about the change,” he said. “Iraq is in a far, far better place than it was, say, 18 months ago.”

However, he warned, those gains could be in jeopardy if U.S. interest in the country is allowed to flag. “So I think what Americans need going forward is a sense of strategic patience,” he said.

“If we decide we are tired of it, if we decide we don’t want to do it anymore and that it is time to turn our attention to other things, this could all go the other way,” Crocker warned. “And it is certainly my sense as someone who has served in the Middle East for the better part of three decades, that you would pay a major long-term price.”

He suggested it could be seen as a repeat of the U.S. withdrawal from Lebanon in the early 1980s, a move that led countries like Iran and Syria to draw assumptions about U.S. lack of resolve and to embrace an attitude of defiance. “These kinds of actions have profound and very far-reaching consequences,” he said.

The talks on the military pact have hit an impasse recently over U.S. insistence on retaining sole legal jurisdiction over American troops and differences over a schedule for the departure of the U.S. military. Iraqi officials have said that they want all foreign troops out by the end of 2011.

Crocker said it is becoming obvious that Iran wants the current negotiations to fail.

“The evidence is pretty clear,” said the ambassador. “It is the stream of public statements coming out of Tehran, political and clerical figures, all criticizing the agreement. So they are being very open about their interference.”