Secretary of State John Kerry will leave for Geneva on Friday to help further nuclear talks with Iran, raising the prospects for a potential deal.

“After consulting with EU High Representative Ashton and the negotiating team on the ground, Secretary Kerry will travel to Geneva later today with the goal of continuing to help narrow the differences and move closer to an agreement,” said State Department spokesperson Jen Psaki in a statement.

Kerry’s trip comes as the administration presses to close a deal with Iran over its nuclear program. Iran says the program is for peaceful energy purposes, but the international community fears Tehran is building a nuclear weapon and has instituted crippling sanctions.

The Obama administration’s blueprint would allow for temporary, limited sanctions relief in exchange for Iran freezing some elements of its nuclear program. Iran’s compliance would open the door to further talks.

That effort has faced strong opposition on Capitol Hill and from key allies, who fear Obama will undercut the international sanctions regime and ease pressure on Iran. The administration has asked lawmakers to hold off on plans to pass a new round of sanctions against Iran, urging more time for diplomacy.

Senate Intelligence Committee Chairwoman Dianne Feinstein, D-Calif, has backed the administration’s approach and said she opposes additional sanctions on Iran.

“The purpose of sanctions was to bring Iran to the negotiating table, and they have succeeded in doing so,” Feinstein said last week. “Tacking new sanctions onto the defense authorization bill or any other legislation would not lead to a better deal. It would lead to no deal at all.”

Other lawmakers, though, say they will push ahead with tougher sanctions to raise pressure on Iran.

A bipartisan group of 14, including Sens. John McCain, R-Ariz., Robert Menendez, D-N.J. and Charles Schumer, D-N.Y., in a statement on Thursday said they are “committed to preventing Iran” from acquiring nuclear weapons.

“We will work together to reconcile Democratic and Republican proposals over the coming weeks and to pass bipartisan Iran sanctions legislation as soon as possible,” the senators said.

Obama defended his diplomatic efforts last week, saying that the U.S. will lose “nothing” by pursuing talks.

The president said that sanctions could be ramped up quickly if Iran failed to honor its commitments.

“Let’s see if this short-term, phase one deal can be completed to our satisfaction,” Obama said. “Let’s test how willing they are to resolve this diplomatically and peacefully.”

This story was published at 3:54 p.m. and has been updated.