For U.S. President Barack Obama, the interim deal to cap Iran's nuclear program is a belated down payment on the transformative foreign policy he always envisioned.

That is one reason why his Republican foes are suspicious of the pact, viewing it as typical of a diplomatic doctrine rooted in weakness and an over eagerness to engage America's enemies at the expense of its friends.

Saudi Arabia cautiously welcomed on Monday a nuclear deal reached between Iran and world powers, saying "good intentions" could lead to a comprehensive agreement on Tehran's controversial atomic program.

"This agreement could be a first step towards a comprehensive solution for Iran's nuclear program, if there are good intentions," the government said in a statement.

The EU ambassador-designate to Israel, Lars Faaborg-Andersen, on Monday sought to reassure the Israelis over a nuclear deal struck with Iran.

Iran agreed to curb its nuclear program for the next six months in exchange for limited sanctions relief following marathon talks with the five permanent members of the U.N. Security Council plus Germany in Geneva that ended Sunday.

Qatar is the latest Gulf Arab state to welcome the nuclear deal between Iran and world powers, calling it a step toward greater stability in the region.

The Gulf's main political power, Saudi Arabia, has previously expressed unease about U.S. outreach to Iran. The dialogue helped along efforts by Washington and others to strike a deal with Iran seeking to ease Western concerns that Tehran could move toward nuclear weapons.

Washington's point man on North Korea on Monday hinted at more sanctions against Pyongyang over its atomic weapons program in the wake of Iran's nuclear deal with world powers.

Glyn Davies, the U.S. special representative for North Korea policy, said he hoped quickening diplomacy examining when to resume stalled six-party talks would bear fruit.

Asian markets rose Monday following another record close on Wall Street, while oil prices fell after Iran struck a deal on its nuclear program that will see eased sanctions on the oil producer.

The generally positive sentiment sent the yen sinking against the dollar, while it also hit a four-year low versus the euro.

Speaker Nabih Berri on Sunday hoped a landmark nuclear deal between Iran and world powers will pave the ground for a “settlement” in war-torn Syria, after he arrived in Tehran for an official visit.

Speaking to reporters at an airport in the Iranian capital, Berri thanked his Iranian counterpart Ali Larijani for inviting him to visit the Islamic republic, hoping his talks there will “strengthen relations between the two countries, especially that this visit comes amid a very delicate period.”

European Union President Herman Van Rompuy on Sunday hailed the "courage" shown by Iran and world powers in their deal to curb Tehran's nuclear program, but also urged its "punctual" implementation, as U.N. chief Ban Ki-moon said the agreement could be "historic" for the Middle East.

"It is now crucial to ensure punctual implementation of the agreement reached and to continue working, on the basis of the trust that is being built, towards a definitive settlement of this issue," Van Rompuy said of the agreement which offers Iran in exchange limited sanctions relief.

Israel's Prime Minister Benjamin Netanyahu on Sunday slammed a nuclear deal between Iran and world powers as a "historic mistake,” his spokesman said.

"PM Netanyahu: What was achieved yesterday in Geneva is not a historic agreement but rather a historic mistake," Ofir Gendelman posted on his official Twitter account, quoting Netanyahu's comments to a weekly cabinet meeting.

U.S. President Barack Obama hailed an historic interim deal with Iran Saturday as "an important first step" towards a comprehensive accord to end the dangerous showdown over Teheran's nuclear program short of war.

Obama, speaking at the White House after the deal was clinched between the P5+1 world powers and Iran in Geneva, said the agreement had for the first time in a decade halted progress on Iran's nuclear program.