New Delhi, May 21 -- British Prime Minister Keir Starmer said Wednesday that Britain's support for Ukraine remains steadfast, despite the U.K. delaying some new sanctions on Russian oil because of a cost-of-living squeeze triggered by the effective closure of the Strait of Hormuz.

A trade license that came into effect Wednesday permits the import of Russian oil that has been refined into jet fuel and diesel in third countries such as India and Turkey. The U.K. announced in October that it would ban imports of those products.

The U.S.-Israeli war on Iran and Iran's retaliatory grip on the strait, through which about a fifth of the world's oil usually passes, has sent fuel prices soaring around the world and sparked concerns about a short...