In a bid to iron out the differences on the India-United States civil nuclear energy cooperation agreement, Prime Minister Manmohan Singh [Images] on Tuesday met Communist Party of India-Marxist general secretary Prakash Karat.

Both sides said efforts would be made to sort out the issues.

Dr Singh and External Affairs Minister Pranab Mukherjee had a breakfast meeting with Karat and discussed issues related to the bilateral civil nuclear cooperation agreement between the two countries.

"Karat and the prime minister reiterated that efforts would be made to sort out the issues," Prime Minister's Media Advisor Sanjaya Baru said in a brief statement.

Some of the points regarding the agreement were discussed during the meeting, Baru said, adding Karat stated that he would put it to the party's Politburo which will meet over the weekend.

The meeting comes a day after the prime minister made a strong defence of the deal in Parliament, saying the country retained the strategic autonomy and sovereign right to conduct a nuclear test.

The recent tension in relations between the UPA government and crucial Left allies heightened after the prime minister dared the Left parties to withdraw support to the government on the issue, saying the deal cannot be renegotiated.

The Left hit back reminding the government that it was running on their support and asked whether it wanted to run the government.

Politburo member Brinda Karat denied that there has been any change in the stand of her party following the meeting between Dr Singh and Karat.

"Our general secretary went and met the prime minister. There has been no change in our stand. All that we are saying is don't implement the deal till certain issues are dealt with," she said.

Communist Party of India general secretary A B Bardhan too said. "They are sticking to their stand and we feel that the stand taken by us is correct."

Asked why the CPM is taking so long to give its reaction, Nilotpal Basu said that this is not unusual. "When the treaty was announced and the text released, even then we took time to react," he pointed out.