A landmark nuclear deal with Tehran does not mean an alignment with Iran, British Prime Minister David Cameron said Friday, as Western powers scrambled to reassure regional allies.
The nuclear accord was struck in Vienna this week after almost two years of negotiations which culminated in a final 18-day stretch of virtually round-the-clock talks.
It put strict limits on Tehran's nuclear activities for at least 10 years designed to stop the country developing a nuclear weapon, in return for lifting sanctions that have crippled Iran's economy.
Now the United States and Britain are engaged in careful diplomacy with Middle Eastern allies such as Saudi Arabia and Israel in a bid to ease concerns that Iran cannot be trusted to implement the deal.
"By signing this deal, Britain is not aligning with Iran," Cameron said in an interview with news channel Al Arabiya, according to a transcript released by his Downing Street office.
"By signing this deal, Britain -- with allies including America, Germany, France, Russia and China -- what we're doing is taking Iran away from a nuclear weapon. "That is good for the region, that is good for regional stability, but we're not aligning with Iran."
US Defense Secretary Ashton Carter travels to Israel and Saudi Arabia next week, while Secretary of State John Kerry is also going to the Gulf next month to try and allay fears.
Cameron's Foreign Secretary Philip Hammond was in Israel last week where he met Prime Minister Benjamin Netanyahu, who has called the deal with Israel's arch-foe a "historic mistake" and hinted at a possible military response.
'Tough as we've always been'
The White House said on Friday that Saudi Foreign Minister Adel al-Jubeir had "welcomed" the recent nuclear deal with Iran in a meeting with US President Barack Obama.
But diplomats from Sunni power Saudi have privately expressed grave misgivings the agreement may legitimise their Shiite rival Iran, which Riyadh accuses of fomenting unrest in Yemen and elsewhere in the Middle East.
In a separate statement, the Saudi embassy said Jubeir "reaffirmed Saudi Arabia's support for an agreement that prevents Iran from obtaining a nuclear capability".
Iran has always denied Israeli and Western charges that it was seeking to build a nuclear bomb, insisting its nuclear programme is for peaceful energy and medical purposes only.
In the interview, Cameron vowed to remain "as tough as we've always been" on Iran over its close relationship with Syria and "support for terrorism".
"Of course we shouldn't be naive about the Iranian regime and some of the things they do and we need to call them out on those things," the British premier added.
The UN Security Council is expected to endorse the deal on Monday, diplomats said.
The resolution is expected to pass without difficulty as its five veto-wielding permanent members -- Britain, China, France, Russia and the United States -- negotiated the accord, along with Germany.
Obama told critics of the deal that they were at odds with "99 percent" of the world on Wednesday.
He said that the issue could either be resolved "diplomatically, through a negotiation, or it's resolved through force. Through war. Those are the options".
The president is facing opposition from Republican rivals, who hope to scupper the agreement in a planned Congressional vote. Obama has said he will veto any attempt to block the deal.
Meanwhile, Iran's supreme leader Ayatollah Ali Khamenei has warned President Hassan Rouhani that "some of the six states participating in negotiations are not trustworthy at all," without saying which.