NEW YORK, April 21 -- US and European stocks reversed Monday as oil prices surged over fears hostilities could resume in the weeks-long Middle East war after Iran closed the Strait of Hormuz following its brief reopening.

Investors were on edge approaching the end of the US-Iran ceasefire, with Washington saying it will send a delegation to Pakistan for a new round of talks "soon" and Iran saying it had yet to decide whether to attend.

"The market mood is very different at the start of the week compared to Friday," said Kathleen Brooks, research director at trading group XTB.

Crude had plunged Friday after the Islamic republic said it would again allow ships to pass through the Strait of Hormuz, through which a fifth of global oil and ...