"We have set the end of July as a notional date and we are certainly going to try meet that date," Ambassador Ryan Crocker told reporters during a brief visit to Washington.
The US government says it is negotiating a legal framework aimed not at establishing permanent bases in Iraq but at keeping security policy options open for both countries beyond 2008 when the UN mandate for US forces ends.
The ambassador acknowledged difficulties in the negotiations for the so-called Status of Forces Agreement.
"There has been a lot of debate. Certainly one of the indicators that this is a new Iraq was Iraqis across the political spectrum expressing views on the negotiations and the agreement," Crocker said.
"In terms of criticism from the neighbors, Iran in particular, I think this is deliberately intended to make the negotiations difficult," he said.
The proposed pact has come under fire from religious and political leaders both in Iraq and in neighboring Iran with anti-American cleric Moqtada al-Sadr vowing to keeping up protests until the deal is scrapped.
The Iraqi government Tuesday said it had a "different vision" from the United States over the deployment of American troops in the country beyond 2008 and vowed not to compromise national sovereignty.
Prime Minister Nuri al-Maliki and US President George W. Bush signed a non-binding statement of principles in November for the negotiations, which began in March with the aim of concluding a pact by the end of July.
The proposed agreement is aimed at giving a legal basis to US troops after the December 31 expiry of a UN mandate defining their current status.
There are currently about 150,000 US troops deployed in Iraq, which was invaded by US-led forces in March 2003.
Government spokesman Ali al-Dabbagh said the cabinet emphasized the full commitment to protecting Iraq's security, property, and resources in line with international resolutions and the level of protection currently provided.
