A Saudi-led coalition has launched a military operation north of Yemen's port city of Hodeidah
It comes a week after a drone attack by Iran-backed Houthi rebels on two major oil facilities in Saudi Arabia, which resulted in Saudi's oil production being halved.
The coalition said it had destroyed four sites used in assembling remote-controlled boats and sea mines which it said are used to carry out attacks that threaten shipping lines and international trade.
Meanwhile, US Secretary of State Mike Pompeo, who said that Iran was behind the attack, said the US was intent on finding a peaceful way out of the confrontation.
A coalition spokesman said: "These sites are used to carry out attacks and terrorist operations that threaten shipping lines and international trade in the Bab al-Mandab Strait and the southern Red Sea."
The Houthi movement in Yemen, which had claimed responsibility for Saturday's attacks on Saudi oil facilities, said through its Masirah TV that the coalition had breached the UN agreement reached in Sweden.
The Western-backed Sunni Muslim coalition intervened in Yemen in March 2015 against the Yemen Iran-aligned Houthi group after the Houthis ousted the internationally recognised government in Sanaa in late 2014.
The Hodeidah ceasefire and troop redeployment agreement was reached last year at peace talks in Sweden, as a trust-building measure to pave the way for talks to end the war, but stalled for months before the Houthi withdrawal from three Red Sea ports.