The rift on the nuclear deal widened on Monday night with the Left parties rejecting a plea of the government that it be allowed to engage in negotiations with the International Atomic Energy Association, whose chief is arriving in India tomorrow.

CPI(M) general secretary Prakash Karat met United Progressive Alliance chairperson Sonia Gandhi [Images] and conveyed the collective view of the Left parties that the government cannot go ahead with any negotiations with the IAEA or anyone else for operationalising the deal, Left sources said.

External Affairs Minister Pranab Mukherjee and Defence Minister A K Antony as also her political secretary Ahmed Patel were present during Karat's meeting with Sonia during the 30-minute meeting. CPI-M leader Sitaram Yechuri was also present.

The government probably sought the Left's permission so that the nuclear safeguards agreement could be broached with IAEA director General El Baradei, who will meet political leadership in Delhi on Wednesday. He will be in Mumbai on Tuesday.

The widening of the rift comes a day before the UPA and the Left parties will meet in a committee constituted for going into the Left's concerns on the Indo-US nuclear deal which they are strongly opposed to.

It also comes a day after Sonia's sharp but veiled attack on the Left parties opposition to the deal which the Congress sought to play down.