Brent crude futures jumped as much as 5% to $97.83 a barrel, while WTI traded around $95 a barrel, as renewed Iran-Israel fighting threatened to unravel a fragile US-Iran ceasefire and further disrupt energy flows.On the maritime chokepoint front, Iran-backed Houthis declared a full ban on Israeli vessels in the southern Red Sea, warning that any Israeli ship (or linked ship) will be seen as a military target."First: We declare a complete and total ban on maritime navigation for the Israeli enemy in the Red Sea, and we consider all enemy movements to be military targets for our Armed Forces from the moment this statement is issued," the terror group said Monday in a statement.The statement continued, "Second: We affirm that we will meet escalation with escalation, and that our military operations will escalate in line with events, the battle, and in conjunction with the axis of Jihad and Resistance.""Third: We affirm the right of our people and the peoples of our free nation to confront American-Israeli aggression, and that we will not stand idly by in the face of the unjust siege imposed on our people and the peoples of the axis of Jihad and Resistance in Palestine, Gaza, Iran, Lebanon, and Iraq. All enemy attempts will fail, God willing, and our operations will continue as long as the aggression and siege against us and the axis of Jihad and Resistance continue," the statement concluded.The Houthis have announced a "complete blockade" of the Red Sea and the Bab al-Mandab Strait against all vessels linked to Israel.