The leader of Yemen’s Houthis has given Israel a deadline to lift its blockade on Gaza, warning that Yemeni “naval operations” against Israel could restart.

Abdul Malik al-Houthi issued the ultimatum on Friday, suggesting Houthi attacks on Israel-linked shipping could start on Tuesday. “We meet the siege with a siege,” Houthi said, according to The Cradle.

He added that Yemen “cannot stand by and watch the Israeli enemy’s aggressive approach in starving the Palestinian people in Gaza.” On Sunday, Israel tightened the siege on Yemen by cutting electricity.

The Houthis, officially known as Ansar Allah, ceased their attacks on Israel and Red Sea shipping after the Gaza and ceasefire deal was reached but had vowed to intervene if Israel violated the agreement.