A security guard at the Qatari embassy in Paris has been killed, with a suspect arrested, officials said.

The circumstances of the killing, including the method used, were not immediately clear.

The prosecutor’s office said “the use of a weapon is not at this time confirmed”.

French press reports said the guard was killed at around 7am outside the embassy in Paris’ posh 8th district, apparently beaten to death.

Several French media said the suspect appeared to be mentally unstable.

Police refused to comment.

The special prosecutor for terrorism cases was not involved in the case, meaning that terror has been ruled out as a motive.