British foreign secretary William Hague said on Sunday that Israel would not be "wise" to attack Iran over its disputed nuclear programme, saying it should give the diplomatic route a chance to succeed.
Speaking in the wake of attacks on Israeli diplomats blamed on agents of Tehran, Hague said the Islamic republic "has increased in its willingness to contemplate utterly illegal activities in other parts of the world".
But he told BBC television: "I don't think the wise thing at this moment is for Israel to launch a military attack on Iran.
"I think Israel, like everybody else in the world, should be giving a real chance to the approach that we have adopted, of very serious economic sanctions and diplomatic pressure, and the readiness to negotiate with Iran.
"And that's what we now have to make a success of."
In recent weeks, there has been feverish speculation that Israel was getting closer to mounting a pre-emptive strike on Iran's nuclear facilities, but Israel has denied reaching such a decision.
Hague said the Israelis had not shared any such plans with Britain, stressing: "We are not part of any planning to attack Iran.
"We don't take any options off the table... But our approach is 100% diplomatically and economically focused to bring Iran successfully to the negotiating table."
Iran said this week it was ready to resume stalled talks on its nuclear drive, prompting a cautious welcome from the United States and the EU.
"They have indicated in the last few days a new readiness to negotiate. Whether that is going to be on any meaningful basis, one has to be sceptical," Hague said.
Tensions between Israel and Iran flared following bombings in New Delhi, Tbilisi and Bangkok last week, but Iran angrily rejected accusations that it was behind the "terrorist" acts.
Hague declined to attribute blame for the attacks, but said Iran had "clearly" been involved in illegal activities abroad, adding: "This is part of the danger that Iran is currently presenting to the rest of the world."