Any push by Donald Trump to readmit Russia to the G7 gathering of economically advanced nations would be vetoed by the U.K., Boris Johnson’s official spokesperson said Monday.

Trump announced Saturday he is postponing the annual G7 summit, which was due to be hosted in the U.S. in June, until September — and plans to invite four additional non-member nations including Russia.

Speaking to journalists at a daily briefing, Johnson’s spokesperson said that while it was up to host nations to decide which countries could be invited as guests, the U.K. would not support Russia being “readmitted as a member of the group.”

Decisions on G7 membership are subject to the unanimous backing of all members. Russia was ejected from the group — previously the G8 — after its annexation of Crimea in 2014.