JERUSALEM — Having failed to stop Sunday’s signing of a nuclear deal between Iran and six Western powers despite a relentless campaign of criticism, Israeli leaders say their mission now is to ensure that, as several put it, this first step is not the last step.

To influence the final deal that the Obama administration and its partners in the Geneva talks intend to hammer out over the next six months, Israel will supplement its public and private diplomacy with other tools. Several officials and analysts here said Israel would unleash its intelligence industry to highlight anticipated violations of the interim agreement.

At the same time, with many Israelis viewing the United States as having abandoned its credible military threat against Iran, they have stepped up talk of a strike of their own.

Though the White House insists the deal signed Sunday is an interim move intended only to buy time to negotiate an agreement that would prevent Iran from obtaining nuclear weapons, Israel is deeply worried that there will be little further progress. The sanctions relief in the interim accord relieves the pressure that brought Iran to the table, Israeli officials argue, so Iranian leaders might not stay. Further, they say, the so-called P5 + 1 nations that negotiated the pact have not agreed on or clearly identified their final goals, nor outlined the parameters for punitive measures if progress is not made within the deadline.