Amid its keenness to see early implementation of the nuclear deal, a US Congressional delegation on Friday met Prime Minister Manmohan Singh [Images] and is understood to have pointed out that time was running out.

The six-member delegation, led by Gary Ackerman, is believed to have discussed overall bilateral relations, particularly various aspects related to the nuclear deal.

The delegation is understood to have noted the short timelines to complete the nuclear deal considering that the US Congress will adjourn in September and will meet only after completion of presidential poll process in January next year.

Ackerman, who chairs the House Foreign Relations Sub-Committee on South Asia, said on Thursday that the agreement should come back to the Congress for final vote by September, failing which it will not be completed during the tenure of the Bush administration.

He made it clear that the deal would have to be taken up during the next administration if India fails to firm up a safeguards agreement with the International Atomic Energy Agency and get a waiver from 45-nation Nuclear Suppliers Group by August as there will be no "lame-duck" session of the Congress.

As per the Indo-US nuclear deal, India has to firm up safeguards agreement with IAEA and get a waiver from NSG before the agreement is put to 'up and down vote' in the US Congress, necessary for implementation of the agreement.

India has finalised the safeguards agreement with IAEA, but is unable to sign it because of stiff opposition from the Left parties, which are extending crucial outside support to the government.