The head of Israel’s Mossad intelligence agency said on Monday that Iran was behind a string of recent attacks on targets across the Persian Gulf.

Yossi Cohen spoke at an annual security conference shortly before Iran acknowledged that it surpassed uranium enrichment limits set by the 2015 nuclear deal. While Israel has closely watched the recent Gulf crisis, it has said little and kept a distance from the rising tensions between the U.S. and Iran.

In his speech, Cohen listed a series of attacks on oil tankers in the Gulf, oil fields in Saudi Arabia and targets in Baghdad. “I can tell you, with certainty, from the best sources of Israeli and Western intelligence, that Iran is behind the attacks,” he said, adding that they “were approved by the Iranian leadership, and were carried out, at least mostly, by the Revolutionary Guard and their surrogates.”

He did not elaborate.

The incidents have come amidst rising tensions in the Gulf since the U.S. withdrew from Iran’s nuclear deal with world powers last year and began restoring crippling sanctions. Iran’s acknowledgement Monday marked its first major departure from the agreement.

Israel considers Iran to be its greatest threat, citing its support for anti-Israel militant groups, its military presence in neighboring Syria and its suspect nuclear program.

Israel believes Iran is trying to develop a nuclear bomb — a charge Iran denies — and was a leading opponent to the international nuclear deal with Iran. Prime Minister Benjamin Netanyahu has said the deal, which gave Iran relief from sanctions in exchange for curbs on its nuclear program, will not prevent Iran from developing a weapons capability.

Cohen called the accord a “bad agreement” and said that “not the accord, but the determination to confront Iran by any means necessary, is the real buffer between Iran and the bomb.”

Earlier Monday, Syrian state media said that Israeli warplanes had attacked military positions early Monday. The Israeli military declined comment.

But last week, Netanyahu acknowledged that Israel has carried out hundreds of attacks in Syria as part of a campaign to prevent Iran from establishing a permanent military presence there and to keep it from arming its Hezbollah allies.

Cohen said “Mossad is detecting a trend” in response to Israeli actions, and that Iran and Hezbollah “are asking to move some bases to northern Syria, a place that they mistakenly think we will have a harder time reaching.”

Cohen also criticized Tehran’s support for Gaza based militant groups, saying that according to Israeli intelligence “in the last two years Iran gave Hamas and the Palestinian Islamic Jihad over $100 million, the vast majority of which was allocated to military purposes.”

(AP)