A boat of Iranian Revolutionary Guard sails next to Stena Impero, a British-flagged vessel owned by Stena Bulk, at Bandar Abbas port, Iran. (ISNA/WANA Handout via REUTERS)

UNITED NATIONS, July 22 (Xinhua) -- United Nations Secretary-General Antonio Guterres on Monday expressed his extreme concern about recent reported seizures of vessels, including in the Strait of Hormuz.

"The secretary-general stresses the need to respect the rights and duties relating to navigation through the strait and its adjacent waters in accordance with international law," said Farhan Haq, deputy spokesman for the UN chief, at the daily noon briefing.

"The secretary-general urges all concerned to exercise maximum restraint and to refrain from actions that will escalate tensions further," he added.

On Friday, Iran's naval forces seized a British oil tanker in the Strait of Hormuz for what Iran called "failing to respect international maritime rules."

The tanker seizure followed a dispute this week between Iran and the U.S. administration over claims the United States had shot down an Iranian drone in the strait.