A billet of highly enriched uranium. Photo: Wikipedia.

Nine influential Democratic and Republican U.S. Senators said on Monday they were open to suspending the implementation of new sanctions against Iran but only on a quid pro quo basis, Reuters reported.

In a letter to President Barack Obama, the nine senators — six Democrats and three Republicans — said the United States and other countries should consider a “suspension-for-suspension” agreement whereby Iran would suspend uranium enrichment and Washington would suspend the implementation of new sanctions.

Iran, however, is not expected to offer to suspend enrichment during talks set to commence in Geneva on Tuesday.

“If the Iranian government takes these steps in a verifiable and transparent manner, we are willing to match Iran’s good-faith actions by suspending the implementation of the next round of sanctions currently under consideration by the Congress,” the letter read.

The Senators reaffirmed that “a credible military threat” remains on the table and said that current sanctions must be maintained.

The senators signing the letter included Democrats Robert Menendez, chairman of the Senate Foreign Relations Committee, and Charles Schumer, the No. 3 Democrat in the Senate, as well as Republicans John McCain and Lindsey Graham, two of the Senate’s most influential foreign policy voices.