The leader of Yemen's Houthis, Abdul Malik al-Houthi, said on Friday the group would resume its naval operations against Israel if Israel did not lift a blockage of aid into Gaza within four days.
The Iran-aligned movement staged more than 100 attacks on shipping from November 2023, saying they were in solidarity with Palestinians over Israel's war with Hamas in Gaza - and the assaults tailed off in January after a ceasefire there.
Over that period, it sank two vessels, seized another and killed at least four seafarers in an offensive that disrupted global shipping, forcing firms to re-route to longer and more expensive journeys around southern Africa.
Threats against Israel
"We will give a deadline for four days. This deadline is for the (Gaza ceasefire) mediators for their efforts," al-Houthi said.
"If the Israeli enemy after four days continues to prevent the humanitarian aid into Gaza and continues to completely close the crossings, we will resume our naval operations against the Israeli enemy."
On March 2, Israel blocked the entry of aid trucks into Gaza as a standoff over the truce escalated, with Hamas calling on Egyptian and Qatari mediators to intervene.
The Houthis, who control most of Yemen, also said in February they will take military action if the US and Israel try to displace Palestinians from Gaza forcibly.