LONDON- Progress was made on Friday in talks between the European Union and Britain on post-Brexit trade issues affecting Northern Ireland and solutions can be found if London redoubles its efforts, the EU official in charge of the talks said on Sunday.

The two sides agreed last week to intensify efforts to resolve difficulties over trade between Great Britain and Northern Ireland, a British province that shares a land border with EU member the Republic of Ireland. 

"We had some progress on Friday," Maros Sefcovic, vice president of the European Commission, said during an interview with the BBC.

"I'm sure that if Lord Frost and the UK would double their efforts ... we can resolve all the outstanding issues to the satisfaction of the people of Northern Ireland," he said, referring to the chief British negotiator David Frost.

During weeks of verbal sparring, London has repeatedly threatened to invoke Article 16, an emergency brake in the Northern Ireland chapter of the Brexit deal, a move that could trigger a full-blown trade war between the EU and Britain.

Sefcovic last week welcomed a change of tone from the British side and called for that to translate into compromise in the talks about the nitty gritty of the trading arrangements.

Since leaving the EU last year Britain has delayed the introduction of some planned border checks that were designed to avoid the need for a hard frontier between Northern Ireland and EU member Ireland.

London says the checks are disproportionate and threaten Northern Ireland's 1998 peace deal because they create a barrier between the UK mainland and the province, something which is intolerable to the pro-British unionist community there.

The EU says checks are needed to avoid goods entering its single market from the UK side without any controls.

(Reporting by Estelle Shirbon; Editing by Kirsten Donovan and Raissa Kasolowsky) ((estelle.shirbon@thomsonreuters.com;))