By Olivia Le Poidevin

GENEVA, June 15 (Reuters) - The United Nations' human rights chief on Monday welcomed the announcement of a peace deal between the United States and Iran, and urged for maximum restraint by all sides in the region.

"I welcome the announcement that the United States and Iran have agreed on a peace deal that provides for an immediate and permanent ceasefire, the reopening of the Strait of Hormuz, and a framework for further negotiations," said human rights chief Volker Turk.

"At this fragile moment it is clear all sides need to exercise maximum restraint and work to implement the agreement reached quickly and in good faith," he added.

His comments come as U.S. and Iranian officials said they had reached an agreement to end their war and reopen the Strait of Hormuz, a preliminary pact that sent oil prices falling but ​leaves the fate of Tehran's nuclear program to further negotiations.

While still a framework, the deal marked the biggest breakthrough towards resolving the conflict that has killed thousands and upended energy markets since it began ‌with joint U.S.-Israeli strikes on Iran in February.

The U.N. rights chief also voiced alarm over Israeli strikes on populated areas and infrastructure in Lebanon, as well as cross-border attacks by Hezbollah. He called for an immediate end to hostilities, Israel's withdrawal from Lebanese territory and investigations into alleged violations of international law by all parties.

(Reporting by Olivia Le Poidevin Editing by Ludwig Burger and Linda Pasquini)