Britain's Prime Minister Theresa May attends a press conference with Secretary General of NATO Jens Stoltenberg at 10 Downing Street, in London, Britain, June 21, 2018. REUTERS/Henry Nicholls

LONDON (Reuters) - Prime Minister Theresa May told the EU’s Donald Tusk on Monday that Britain would set more details on its vision for a future relationship with the bloc after a June 28-29 summit.

May has struggled to find a proposal on post-Brexit customs arrangements - the biggest stumbling block so far in exit talks - to take into negotiations with Brussels as the clock ticks down to Britain’s scheduled exit in March 2019.

May met European Council President Tusk at Downing Street on Monday. A Downing Street spokesman said May had told Tusk she looked forward to discussing the progress made so far and would set out more detail in a White Paper after the June Council.