LONDON - The historic deal to curb Iran's nuclear programme should be given time to work, but Tehran's intentions must be viewed with deep scepticism, Britain's newspapers said Monday.
The Daily Telegraph argued that the deal was the best option on the table, but that the world needed to be extremely cautious.
"Given that Iran's nuclear ambitions have had no rational purpose except to give its ruthless leaders the option of building the ultimate weapon, we are entitled to approach this deal with deep scepticism and caution," said its editorial.
"But rejecting the deal would have meant that Iran's nuclear programme expanded month by month, until the terrible moment arrived when America would have had little choice but to go to war," it added.
"On balance, we will be safer with this pragmatic agreement than without it. The West, however, should not drop its guard."
Iran agreed to curb its nuclear programme for the next six months in exchange for limited sanctions relief, in a preliminary accord meant to lay the foundations for a comprehensive agreement later this year.
Business publication the Financial Times hailed the pact as "a historic moment" and said that the shadow cast by US military actions in Iraq and Afghanistan meant a peaceful solution was worth striving for.
"Diplomacy has enjoyed few breakthroughs," said its editorial. "The world must give this one a chance."
The left-leaning Guardian said the agreement was "arguably the biggest foreign policy achievement of Barack Obama's presidency and the most significant agreement between the US and Iran since the Iranian revolution."
"If it succeeds, it has the power to reshape the Middle East," added its editorial.
The paper also praised often maligned Catherine Ashton, the EU's high representative for foreign affairs, for pulling off "the biggest diplomatic coup in the history of EU foreign policy."
"On Sunday, she was in the unaccustomed position of being showered with praise. She must be smiling," it said.
However, the centre-right Times slammed the deal as being fraught with danger and "achingly generous" to Iran.
"The record of its past behaviour suggests that Tehran will bank these concessions and then carry on as before," said its leading article. "That is not good enough.
It called Iran's claim to uranium enrichment rights "a fiction."
"The regime's insistence on access to the full fuel cycle is highly suggestive that it wishes to retain freedom of manoeuvre to develop nuclear weapons.
"That option has not been ruled out by yesterday's deal. It ought to have been," it stressed.