The Palestinian ambassador to the Czech Republic has been killed in a blast at his home thought to have been caused when he opened a safe containing explosives.

Czech police said there was no evidence that Jamal al-Jamal had been attacked. But the Czech authorities are bound to demand to know why explosives were being stored at the Palestinian diplomatic mission in Prague.

According to Riad al-Maliki, the Palestinian foreign minister, the safe had not been opened in at least 30 years. It was recently moved from an old embassy building.

"The ambassador decided to open it. After he opened it, apparently something happened inside and [the safe] went off," Maliki said.

The Novinky.cz news site, quoting sources close to the police investigation, said the blast had probably been caused by "careless manipulation with a dangerous explosive".

A Prague rescue service spokeswoman, Jirina Ernestova, said Jamal, 56, had been put in a medically induced coma when he first arrived at Prague military hospital. Daniel Langer, a doctor at the hospital, told public television Jamal had suffered serious abdominal injuries.

A 52-year-old woman was taken from the scene of the explosion to a hospital in Prague suffering from shock. She was not immediately identified.

An embassy spokesman, Nabil el-Fahel, told Czech Radio the ambassador's entire family had been at the two-storey residence in Suchdol, a northern suburb of the Czech capital, when the blast occurred.

A Palestinian official in Ramallah said: "This explosion happened at his house. He recently moved there. He was taken to hospital. An investigation is under way."

A second Palestinian source said: "He moved an old case with him to the new house from the old house. And when he opened it, the explosion happened."

There were no visible signs of damage to the house. Police cordoned off part of the street and half a dozen police vehicles, two firetrucks and two ambulances were present. Police sniffer dogs were at the site.

The Palestinian foreign ministry said it would send a delegation to Prague to help with the investigation.

Jamal had been ambassador to the Czech Republic since October.