Israel is closing schools nationwide over security concerns, military spokesman Daniel Hagari said on Saturday, after Iran threated to retaliate for a deadly air strike on its Damascus consulate.

There will be "no educational activities" when the school week begins on Sunday "in light of the security situation," he said in a televised statement.

The measure is set to last two days, according to online army guidelines.

Iran has vowed retaliation after the presumed Israeli strike on April 1 which levelled its consulate in Damascus, killing seven members of the Revolutionary Guards including two generals.

US President Joe Biden said on Friday that he expected Iran to retaliate "sooner (rather) than later".

Earlier on Saturday Iran's Revolutionary Guards seized a container ship "related to the Zionist regime (Israel)" near the Strait of Hormuz, state media reported.

Israeli Foreign Minister Israel Katz postponed a planned visit to Hungary and Austria which had been scheduled to begin on Sunday "due to the security situation," his spokesman said.