PRAGUE, Jan. 2 -- Czech police found some weapons that had not been registered in the Czech Republic in the expolded building of Palestinian embassy, said Prague police chief Martin Vondrasek on Thursday.

He said policemen found a number of traces during the investigation into the explosion of a safe that killed Palestinian ambassador Jamal Al Jamal in the embassy building in Prague-Suchdol neighborhood on Wednesday, but he refused to specify the number and types of the unregistered weapons or release other details.

"Genetic and ballistic examinations will follow," said Vondrasek.

Czech diplomacy is concerned about the weapons that were found at the Palestinian embassy in Prague.

"The Vienna Convention on Diplomatic Relations may have been violated and we will demand an explanation from the Palestinian Authority," Foreign Ministry spokeswoman Johana Grohova said.

"The conditions of the acquisition, ownership, possession and use of weapons and ammunition and the rights and duties of weapon and ammunition holders are set by law No 119/2002 on arms and ammunition of the Digest of Laws. The provisions of this law apply also to the persons who enjoy diplomatic privileges and immunity," said the spokesperson.

The police will now investigate how the weapons have got to the embassy.

The Palestinian ambassador was killed on Wednesday by an explosion caused by inexpert manipulation of a safe in the sitting room, according to initial police investigation.

The ambassador officially assumed the post on Oct. 11, 2013. He moved to the residence where is to be a new seat of the Palestinian embassy a few days ago.