The United States has said that it has made some progress on a proposed agreement to operationalise the civilian nuclear deal with India but there is still 'some work' left to be done.

"I do not have a detailed readout for you. I know that they did make some progress, but there is still work left to be done," State Department Spokesman Sean McCormack told media persons at a briefing in Washington.

Asked about the latest visit of Under Secretary of State for Political Affairs Nicholas Burns to India for talks with Foreign Secretary Shivshankar Menon on the '123 Agreement' and the status of the negotiations, he said: "Let me do a little research for you and see if I can get back to you on exactly when the experts will reconvene. But they did make some progress, but there is still work left to be done."

The two countries are aiming at sorting out differences particularly on issues like reprocessing right, perpetuity of fuel supplies and continuance of the civilian nuclear cooperation if India were to conduct an atomic test.