NEW DELHI: US lawmakers' letter pressing India to back off from its engagements with Iran to save the nuclear deal drew sharp reaction in the Rajya Sabha from government's Left allies and Opposition BJP which demanded a statement from Prime Minister Manmohan Singh on the issue.

Responding to concerns and allegations that national interest and sovereignty were being compromised by the government in talks on the deal, Parliamentary Affairs Minister P R Dasmunshi assured the House that the Prime Minister will be informed of the sentiments of the members and said "I am sure he will make a statement."

Soon after the Rajya Sabha met, Yashwant Singh (BJP), Brinda Karat (CPM) and Digvijay Singh (JD-U) were on their feet terming the letter as an "open threat" and interference in the country's internal affairs.

Sinha said the government has not taken Parliament into confidence in the negotiations on the deal. "Dangerous developments are taking place... Most dangerous if the Congress government is buckling under US pressure to accept the terms prescribed in the Hyde Act."

"We must send a strong message to the US Senators that such pressures will not be tolerated," he said on the letter sent to the Prime Minister. Karat said the letter by the US lawmakers was an "open threat" to the sovereignty of the nation and it was essential for the House to condemn it.