The Czech Foreign Ministry says Palestinian authorities have apologized for illegal weapons that were discovered at the Palestinian embassy complex in Prague where a possibly booby-trapped safe killed the ambassador.

In a statement Tuesday, the ministry says the Palestinians have promised to take measures to prevent such incidents in the future.

Police found 12 unregistered weapons in a search following the explosion. The Czechs said the arms were in breach of international obligations.

Ambassador Jamal al-Jamal died Jan. 1 after an embassy safe exploded. The career diplomat had only started his posting in October.

The Palestinians previously said the weapons were not illegal and dated to the Cold War.

It remains unclear what caused the safe to explode but the ambassador's death is being investigated as a case of negligence.