By Elwely Elwelly, Ahmed Elimam and Eman AbouhassiraDUBAI, July 23 (Reuters) - U.S. President Donald Trump promised on Thursday "major military punishment" for Iran and its Houthi allies, after the Yemeni fighters struck two Saudi oil tankers in the Red Sea, extending the Middle East war to a second major shipping chokepoint.The prospect that disruption could widen to a second sea sent global oil prices surging in one of the steepest rises of the war. Brent crude rose more than 6%, breaking through $100 a barrel for the first time since May.

Houthi threats, Iranian strikes and a Hormuz standstill send oil surging as the US-Iran conflict enters its 10th day.

In another escalation, the US president said American forces would broaden bombing to a nuclear site called Pickaxe Mountain, 220 kilometres south of Tehran.