US Secretary of State John Kerry held talks with Israel’s leaders in Jerusalem Sunday on the deal reached by the US and Russia Saturday aimed at destroying the Assad regime’s chemical stockpile by the middle of next year.

At a joint press conference with Prime Minister Benjamin Netanyahu, Kerry insisted that the option for US-led military intervention would remain on the table in the event that the agreement was not honored.

“This will only be as efficient as its implementation will be,” Kerry said, referring to the US- and Russia-brokered deal, which calls for Assad to be stripped of all chemical weapons by mid-2014. “And President Obama has made it clear that to accomplish that, the threat of force remains.”

Kerry stressed that it was crucial for Syria to honor the agreement. Otherwise, the US would wield military force against Syria. Kerry said that “the threat of force is real” if Syria does not carry out the plan to hand over its chemical weapons.

Kerry added: “We cannot have hollow words in the conduct of international affairs.” He told reporters that the accord “has the full ability… to strip all of the chemical weapons from Syria.”

In comments aimed at his hosts, Kerry said the deal, if successful, “will have set a marker for the standard of behavior with respect to Iran and with respect to North Korea and any rogue state, [or] group that tries to reach for these kind of weapons.”

The instances of chemical weapons use, Kerry said, “are crimes against humanity and they cannot be tolerated.”

Netanyahu thanked Kerry for his efforts to purge Syria of chemical weapons and linked the agreement with Syria to the ongoing campaign to curb Iran’s controversial nuclear program.

“We have been closely following – and support – your ongoing efforts to rid Syria of its chemical weapons,” Netanyahu said. “The Syrian regime must be stripped of all its chemical weapons, and that would make our entire region a lot safer.

“The world needs to ensure that radical regimes don’t have weapons of mass destruction because as we’ve learned once again in Syria, if rogue regimes have weapons of mass destruction, they will use them. The determination the international community shows regarding Syria will have a direct impact on the Syrian regime’s patron, Iran. Iran must understand the consequences of its continual defiance of the international community, by its pursuit toward nuclear weapons… if diplomacy has any chance to work, it must be coupled with a credible military threat.”

Netanyahu earlier Sunday expressed cautious optimism about the deal, stressing that the proof of its effectiveness would be in deeds, not words.

Officials in Jerusalem said late Saturday Israel would of course be delighted to see the Assad regime stripped of chemical weapons, but that Israel was extremely wary of the unfolding diplomatic framework, and concerned that Assad was bent on buying time and that the optimistic timetable set out in Saturday’s agreement would not be adhered to.

Kerry and Netanyahu were also talking Sunday about the US-brokered Israeli-Palestinian peace talks which resumed in late July. This is Kerry’s first visit to the region since the resumption.

The Palestinians have complained that Israel was not negotiating seriously on all core issues and was focusing overwhelmingly on border concerns. Israeli officials have said that the current instability in the region underlines Israel’s demand to retain a military presence in the Jordan Valley under any accord.

Kerry was to have met with Netanyahu later this week in Rome, but Netanyahu canceled his planned trip amid the current regional tensions.