Czech police have confirmed they discovered an explosive device at the Palestinian embassy in Prague where a possibly booby-trapped safe killed the ambassador on New Year's Day.

Prague police spokesman Tomas Hulan today told AFP the device was found during a sweep of the embassy and had been sent to a forensic lab for analysis.

He refused to provide further details or to confirm or deny media reports that the explosive was found inside a book.

Ambassador Jamal al-Jamal, 56, died on 1 January in a blast that went off shortly after he opened a safe.

Police have ruled out foul play.

But the late diplomat's daughter Rana al-Jamal has said she believes her father was murdered.

After the blast, police found 12 firearms at the embassy, including submachine guns and sidearms that were not officially registered in the Czech Republic.

Palestinian officials told Czech police that communist authorities gave the arms to Palestinian diplomats in Prague as a gift, according to Hulan.

On Tuesday, Palestinian diplomats issued an official apology for the "illegal presence of weapons" at the embassy and for "the incident that resulted in the tragic death of" Jamal, according to a Czech foreign ministry statement.