LONDON/MUMBAI, Oct 7 (Reuters) - Britain said it was seeking urgent clarification on steel import quotas announced by the European Commission on Tuesday, with Prime Minister Keir Starmer saying his government was in talks with the bloc about the move.

The European Commission proposed cutting tariff-free steel import quotas by almost half and a 50% duty for excess shipments in a bid to preserve viable steelmaking in the European Union (EU).

Britain's steel industry has warned of an existential threat from the proposed EU tariffs, the impact of which could exceed that of U.S. President Donald Trump's tariffs on the sector.

Asked whether Britain was seeking an exemption, Starmer declined to give details but said he would give strong support to the sector and would "be able to tell you more in due course."

"I’m not going to go into the details, but I’m going to tell you in clear terms as you would expect we are discussing this with the EU and with the US," he told reporters on a plane en route to India for an official visit.

Britain currently faces U.S. tariffs of 25%, below the 50% faced by other countries after Britain reached a deal with Trump in May, with British officials trying to lower the tariff further to 0% under a quota.

Britain said in August the EU would remove tariffs on key steel products under a quota system as part of a reset of ties and a recent deal to ease trade barriers.

British industry minister Chris McDonald said Britain was "pushing the European Commission for urgent clarification of the impact of this move on the UK".

"It's vital we protect trade flows between the UK and EU and we will work with our closest allies to address global challenges rather than adding to our industries’ woes," he said.