The future of India's proposed nuclear deal with the United States remains uncertain, with the postponement of a key meeting between India's government and its communist allies.

The talks were set to take place Wednesday in New Delhi, but communist leaders say the meeting will now take place on June 25.

The delay comes as India's left wing parties reffirm their opposition to the agreement, saying it undermines India's independent foreign policy and nuclear weapons program.

Indian Foreign Minister Pranab Mukherjee (l) looks on as Communist Party of India leader Prakash Karat, (r) leave after the meeting on the Indo - U.S. nuclear deal in New Delhi, 17 Mar 2008

Indian Foreign Minister Pranab Mukherjee met with communist leader Prakash Karat Monday, seeking approval for India to sign an agreement with the International Atomic Energy Agency (IAEA).

But communist party leaders say such an agreement with the IAEA is unacceptable as it would allow the U.S. deal to go forward.

The proposed nuclear deal would allow India to trade nuclear fuel and technology.  India would also submit some of its civilian nuclear reactors to United Nations monitoring

Indian Prime Minister Manmohan Singh said last week the agreement would allow India to have civilian nuclear cooperation with other countries, which is crucial to India's energy security.

In addition to the IAEA, the deal must also be approved by the Nuclear Suppliers Group and the U.S. Congress.

Some information for this report was provided by AP and Reuters.