TEHERAN • The British government is stepping up pressure on Iran to release a British oil tanker seized in the Strait of Hormuz, an incident that sent tension soaring in one of the world's critical energy choke points.

The United Kingdom has demanded the immediate release of the Stena Impero and yesterday summoned Iran's charge d'affaires, Mr Mohsen Omidzamani, in London.

The government threatened Iran with "serious consequences" and advised British ships to avoid the area.

Foreign Secretary Jeremy Hunt said in a tweet that British shipping will be protected.

Tensions have been flaring in the Strait of Hormuz in recent weeks as Iran lashes out against US sanctions that are crippling its oil exports and the seizure of one of its tankers near Gibraltar.

BLOOMBERG