Protesters gathered outside the Myanmar embassy in London on Wednesday following reports that the ambassador had been locked out and barred from entering the building.
Ambassador Kyaw Zwar Minn told the Daily Telegraph that Myanmar military figures had taken over the diplomatic mission.
"When I left the embassy, they stormed inside the embassy and took it. They are from the Myanmar military," he said.
"They said they received instruction from the capital, so they are not going to let me in," he added.
"They are not able to do this. The British government won't allow this one, you'll see that."
Britain's Foreign Office would not confirm or deny the reports.
Metropolitan Police said that they were "aware of a protest" outside the building in the Mayfair neighbourhood, and that public order officers were in attendance.
Britain has been a strong critic of the Myanmar military since it seized power there in February, and last week ramped up sanctions against business conglomerates wholly or partially overseen by generals.