Top US diplomat Mike Pompeo and Israeli Prime Minister Benjamin Netanyahu on Wednesday vowed to counter Iranian "aggression" as the two met in Jerusalem just weeks ahead of Israel's elections.

Netanyahu said US President Donald Trump's pressure on Iran was already having an effect, referring to his withdrawal from the landmark 2015 nuclear deal between Tehran and world powers and the reimposition of sanctions.

"We need to increase it, we need to expand it, and together the United States and Israel are working in close coordination to roll back Iranian aggression in the region and around the world," the premier told journalists after Pompeo arrived.

Pompeo spoke of a Middle East conference in Warsaw last month that included Arab nations as well as Israel, saying the discussions involved efforts "to stop Iran's regional rampage" among other issues.

The US secretary of state also noted Iranian calls for Israel's destruction.

"With such threats a daily reality of Israeli life, we maintain our unparalleled commitment to Israel's security and firmly support your right to defend yourself," he said.

Netanyahu reiterated his pledge to keep Iran from entrenching itself militarily in neighbouring Syria, where the Islamic republic backs President Bashar al-Assad's regime.

Israel has carried out hundreds of air strikes there against what it says are Iranian and Hezbollah targets.

"There is no limitation to our freedom of action, and we appreciate very much the fact that the United States backs up our actions as we do them," Netanyahu said.

The premier, facing a stiff challenge from a centrist alliance in April 9 polls, will also visit Washington next week and meet with Trump twice while there.