US urges Iran reply by September
US Defence Secretary Robert Gates has urged Iran to respond to US diplomatic overtures by September, BBC reported.
His Israeli counterpart Ehud Barak indicated that military action remained an option on Iran, following talks with Mr Gates in Jerusalem.
Senior US officials are engaged in a drive to breathe new life into faltering regional peace moves.
US envoy George Mitchell met Egypt's Hosni Mubarak, as well as Israel's president and the Palestinian leader.
He has already been in Syria, drumming up regional support for the new US initiative.
Both Mr Mitchell and Mr Gates - as well as two other senior US envoys - are meeting Israeli leaders as part of the bid to revive the Israeli-Palestinian peace process, which has been stalled for six months.
US-Israeli relations have become strained since US President Barack Obama demanded a halt to all Israeli settlement building in the occupied West Bank.
Shortly after coming to office in January, Mr Obama made an overture to Iran, saying that if it and countries like it were "willing to unclench their fists, they will find an extended hand from us".
But Israel says Iran's alleged nuclear ambitions remain its number-one concern and in recent weeks the US has expressed dismay about Iran's suppression of protests over disputed presidential elections.
Iran denies claims it wants to build nuclear weapons, saying it is enriching uranium for a civilian energy programme.
On Monday, Mr Gates said the US offer to Iran was "not open-ended", echoing comments by US Secretary of State Hillary Clinton earlier this month.
Mr Obama was hoping for a response by the time of the UN General Assembly in September, Mr Gates added.
Mr Barak cautioned that "no option" had been removed in its handling of Iran - suggesting military force remained a possibility - though "priority should be given still to diplomacy and sanctions".
The two men struck a conciliatory tone, with Mr Gates speaking of a "good meeting" with Mr Barak and reaffirming America's "strong commitment" to Israel's security.
Mr Barak said he was "extremely thankful for US support [on defence] - financial and technological".
Mr Gates later held talks with Prime Minister Benjamin Netanyahu. The Israeli leader's office said in a statement that he had emphasised the need to use "all available means" to prevent Iran developing nuclear weapons.
Mr Gates then travelled to Jordan for a meeting with King Abdullah, with the Palestinian issue and defence ties on the agenda.