WASHINGTON, July 14 (Reuters) - Two influential U.S. senators have asked fellow lawmakers to support demands that Iran accept tough conditions in nuclear talks, including at least two decades of inspections, before Congress would agree to ease sanctions.
The appeal was made as Iran and six major powers, including the United States, approach a deadline in talks in Vienna aimed at a deal in which Iran would curb its nuclear program in exchange for gradual relief from crippling economic sanctions.
Democrat Robert Menendez and Republican Lindsey Graham, who believe President Barack Obama's administration should not act without Congressional backing, distributed a letter among senators saying they want Iran to "come clean" about any military dimensions of its nuclear program.
They accused Tehran of a "history of deception in its nuclear program," and said they feared long-term U.S. concerns would not be addressed in any agreement. Rather, a deal ending U.S. sanctions may "provide Iran a window for economic recovery whereafter it could resume its nuclear program," they said.
It was unclear how much support the letter, a copy of which was obtained by Reuters on Monday, would attract among the 100 senators.
Menendez, chairman of the Senate Foreign Relations committee, and Graham, a member of the Senate Armed Services Committee, also called for immediate resumption of sanctions if Iran did not keep its commitments.
The letter sought signatures by Wednesday, four days before the July 20 deadline for an agreement
With both sides complaining of scant progress, U.S. Secretary of State John Kerry met Iranian Foreign Minister Mohammad Javad Zarif in Vienna on Monday for a second day to push for "critical choices" on Tehran's nuclear program.
Some activists who advocate an agreement criticized the letter as an attempt by hawkish lawmakers to derail the talks.
"The Senate should be careful not to unnecessarily complicate the process at this critical stage. Otherwise they may be the ones who get the blame for the consequences," said Daryl Kimball, executive director of the Arms Control Association.
The Senate's Democratic leaders early this year blocked a bill from Menendez and Republican Mark Kirk that would have cut Iran's oil exports to almost zero and reduced Obama's power to waive sanctions if Tehran violated an interim deal.
Lawmakers and congressional aides told Reuters last week they expected Senate leaders would step in again if hawkish lawmakers attempted to pass legislation deemed detrimental to the talks.
Adam Sharon, a spokesman for Menendez, said the letter was not an attempt to derail the talks.
"There is a role for Congress to play, and it's a role Congress has played for about a decade," he said, noting that U.S. lawmakers had pushed for the current sanctions regime, which helped bring Iran to the negotiating table.
He would not say how many lawmakers had signed the letter, which was first distributed to senators on Friday.
Reporting by Patricia Zengerle; Editing by David Storey and Lisa Shumaker