Dr Singh is still ill and resting, his media adviser Dr Sanjaya Baru told rediff.com on Saturday morning. The prime minister, who is reported to be running a viral fever, has cancelled all his appointments since Thursday, June 19, giving rise to speculation that he may resign if the nuclear deal is abandoned by his Congress party and its UPA allies to avoid an early election.

Meanwhile, Mukherjee, the Congress party's go-between with the Communists and its UPA allies, deferred an official visit to Australia so that he could try and convince the Left leaders on Saturday to soften their stand on the nuclear deal.

Karat meanwhile told The Telegraph newspaper that the Left will break away from the UPA if the government insists on taking the nuclear treaty to the International Atomic Energy Agency in Vienna.

The Telegraph felt the Left could pull down the government to ensure that a minority government does not go ahead with the nuclear deal.

"The situation is neither good or has worsened," Mukherjee told the media on Friday after an unscheduled meeting with Karat. Agriculture Minister Sharad Pawar [Images] also spoke to Karat in an effort to break the deadlock.

Should the 60 Left MPs withdraw support to the UPA, the Congress may seek backing from the 38-member Samajwadi Party to save the government. The Congress has 153 MPs in the Lok Sabha; its other UPA allies include the Rashtriya Janata Dal (24 MPs), the Dravida Munnetra Kazgham and Nationalist Congress Party (16 and 11 MPs respectively), the Pattali Makkal Katchi (6), Jharkhand Mukti Morcha (5) and Ram Vilas Paswan's Lok Janashakti party (4).

Though the government had offered to talk to the Left parties on June 25, the meeting could be pushed to Saturday next, June 28, because Mukherjee is away.