0813 GMT February 22, 2020
"The intensive raids on Hodeida are a serious escalation that could torpedo the Sweden agreement," one of the fighters' leaders, Mohammed Abdessalem, said, referring to the UN-supervised truce agreed outside Stockholm in December, AFP reported.
Thursday's strikes were the first reported against Houthis since they claimed a twin attack on Saudi Arabia's oil industry at the weekend.
"The (Saudi-led) coalition will be responsible for the consequences of this escalation and we'll be watching the UN stance on this situation closely," Abdessalem added, in comments reported by the fighters' Al-Masirah television.
The coalition destroyed four sites outside Hodeida used by the fighters to assemble remote control vessels and marine mines, the official Saudi Press Agency reported.
The fighters’ activity at the sites threatened maritime security in the strategic Bab al-Mandeb strait as well as the southern Red Sea, the news agency said.
Shortly before the Hodeida strikes were announced, the coalition said that it had thwarted an attack by a booby-trapped, remote control boat.
The coalition intervened in support of former Yemeni government in 2015 when Abd Rabbuh Mansour Hadi, the then-president, resigned and fled into Saudi exile.
The conflict has since killed tens of thousands of people – most of them civilians – and driven millions more to the brink of famine in what the United Nations calls the world's worst humanitarian crisis.
But the coalition, assisted by Western powers including the US, has struggled to oust the Houthis that have stepped up attacks on targets inside Saudi Arabia.
The fighters claimed responsibility for last Saturday's attacks on Saudi energy giant Aramco's huge Abqaiq processing plant and the Khurais oil field, which halved the kingdom's oil output.
But both Washington and Riyadh have ruled that out and pinned the blame on Saudi Arabia's archrival Iran. Tehran vehemently rejected their allegations.