Japan lodged a protest with the Myanmar military government after security personnel forcibly entered the homes of Japanese Embassy and aid staff in Yangon in April and has demanded steps to prevent a recurrence, the government's top spokesman said Monday.

Chief Cabinet Secretary Katsunobu Kato said at a news conference that while the staff were not harmed, the security forces' actions "risked the safety of the Japanese nationals" and violated the Vienna Convention on Diplomatic Relations.

The treaty stipulates the protection of diplomats from arrest or detention and the inviolability of mission premises.

Kato said the Myanmar military government had apologized for the incidents, which took place on the night of April 17 at the homes of a worker at the Japanese Embassy in Yangon, and a member of the Japan International Cooperation Agency.

Since the military seized power in a coup in February, ousting the democratically elected government of civilian leader Aung San Suu Kyi, at least 890 people have been killed and thousands arrested in violent crackdowns on protesters, according to the Assistance Association for Political Prisoners, a rights group tracking the situation.