WASHINGTON (AP) — US lawmakers from both parties have expressed a willingness to give President Barack Obama’s outreach to Iran a chance to end to Tehran’s nuclear standoff with the West, but at the same time they are crafting tough new US economic sanctions to further isolate the Islamic republic.

Obama’s phone call last week to Iranian President Hassan Rouhani was a groundbreaking conversation. It was the first contact in more than 30 years between the leaders of the two countries and an about-face from when Obama’s predecessor, George W. Bush, included Iran in his “axis of evil” with North Korea and Iraq.

Obama wants Rouhani to prove that he’s willing to curtail some of his country’s uranium enrichment activity, which many believe is being used to give Iran nuclear weapons capability.

Rouhani said Wednesday in Tehran that Iran is open to discussing “details” of its nuclear activities to reach a deal with world powers. He emphasized Tehran’s longstanding position that Iran has a fundamental right to enrich uranium, a key ingredient of nuclear weapons that Iran says it needs for peaceful purposes. But his statement was a veiled hint that Iran is open to negotiate on the level of uranium enrichment as part of a deal in return for lifting of sanctions.

“Iran’s enrichment right is not negotiable, but we must enter into talks” to see what the other side proposes, he said in remarks after a meeting with his Cabinet. Rouhani said Iran had drawn up a “precise plan” to present later this month at the next round of talks with the five permanent members of the UN Security Council plus Germany.

The US engagement with Iran, meanwhile, is straining relations with Israel, a key American ally.

Israeli Prime Minister Benjamin Netanyahu said in a speech Tuesday at the United Nations that the new Iranian president was conducting a “charm offensive.” Iran and Israel see each other as arch enemies. Tehran does not recognize the Jewish state, and supports anti-Israeli militants like Lebanon’s Hezbollah and Palestinian Hamas.

But while Israel is reaffirming its hard-line stance against Iran, the sentiment in Washington’s political circles has softened.

Five years ago, Obama the presidential candidate was hit with criticism for suggesting talks with the Iranians without preconditions. Then during his re-election campaign, Obama was called weak on Iran.

Now, even leading Senate hawks, including his 2008 opponent, John McCain and Lindsey Graham, have backed Obama’s careful engagement effort. They say it is worth testing Iran’s seriousness even if they’re skeptical about Rouhani’s new course of moderation and disdainful of Tehran’s human rights record and alleged support for terrorism.

The debate essentially has shifted away from whether it’s worth talking to Iran to debating the details of engaging Iran, which claims it is not seeking nuclear weapons.

While Obama’s gesture to Tehran hasn’t prompted major Republican criticism, it has fed into domestic arguments over health care and spending levels. Several Republicans in Congress have lambasted the president for appearing “more willing” to talk to Rouhani than to them.

While the current government shutdown may have muted congressional reaction to Obama’s phone call with Rouhani, lawmakers are moving forward on legislation for new sanctions, with plans to tee them up so the president can use enhanced sanctions as part of his negotiating leverage.

In July, the House approved tough new sanctions on Iran’s oil sector and other industries. The bill blacklists any business in Iran’s mining and construction sectors and commits the United States to the goal of ending all Iranian oil sales worldwide by 2015. It also builds on US penalties that went into effect last year that have cut Iran’s petroleum exports in half and left its economy in tatters. China, India and several other Asian nations continue to buy billions of dollars of Iranian oil each month, providing Tehran with much of the money it spends on its weapons and nuclear programs.

No bill would likely be finalized before November. That gives the administration at least several weeks to see whether Iran changes course under Rouhani.

Debate on Capitol Hill about Syria also has changed the dynamic on US ties with Iran.

Lawmakers were reluctant to keep a US military option on the table in connection with the crisis in Syria after the Aug. 21 chemical weapons attack outside Damascus, which, according to administration estimates, killed more than 1,400 people. It’s difficult to see how Congress would support a US military strike on Iran over its nuclear program, and that might strengthen Obama’s case for a diplomatic resolution to the standoff.

Copyright 2013 The Associated Press.