WASHINGTON, Nov 24: The head of a powerful US Senate committee said on Sunday that American lawmakers would provide a six-month window for a nuclear deal with Iran to work.

Although the Obama administration is presenting the deal, reached in Geneva on Saturday, as a major diplomatic achievement, it faces a stiff resistance in the US Congress.

Senator Robert Menendez, Chairman of the Senate Foreign Relations Committee, said while he would support a two-track policy of diplomacy and sanctions with Iran, he did not believe the deal could end Tehran’s alleged pursuit for nuclear weapons.

“In my view, this agreement did not proportionately reduce Iran’s nuclear programme for the relief it is receiving. Given Iran’s history of duplicity, it will demand ongoing, on the ground verification,” the senator said in a statement issued by his office.

“Until Iran has verifiably terminated its illicit nuclear programme, we should vigorously enforce existing sanctions. I do not believe we should further reduce our sanctions, nor abstain from preparations to impose new sanctions on Iran should the talks fail.”

Mr Menendez said he would be monitoring the enforcement of existing sanctions not covered by the interim agreement to ensure they were being “robustly enforced”.

Yet, he agreed to give the Obama administration an opportunity to make the deal work.

“I expect that the forthcoming sanctions legislation to be considered by the Senate will provide for a six-month window to reach a final agreement before imposing new sanctions on Iran, but will at the same time be immediately available should the talks falter or Iran fail to implement or breach the interim agreement,” he said.