A cache of unregistered weapons was found at a diplomatic residence in Prague, Czech Republic, where a Palestinian envoy was killed by an explosion, officials said Friday. Ambassador Jamal al-Jamal died Wednesday after what authorities described as an accidental explosion involving the safe at his home. Officers searching the house following the blast found enough weapons to arm a ten-man combat unit, police said. Local media reported that the haul included assault rifles. Johana Grohová, spokeswoman for the Ministry of Foreign Affairs, told NBC News that the unregistered arms could be a breach of the Vienna Convention and it will "demand" an explanation from the Palestinian authorities. Czech police said they were not treating Wednesday's explosion as an attack or a terrorist incident, but the ambassador’s daughter Rana al-Jamal, 30, told Reuters on Thursday that she believed her father was "deliberately killed."