PESHAWAR, May 6: A small bomb exploded outside a hospital in Tank, about 400km from here, but caused no casualties, police said.

The home-made device, planted alongside the outer wall of the hospital, exploded at around 9:45pm on Monday, a police officer said.

The blast caused minor damage to the wall but no injuries or deaths, he said.

Five foreigners work at the 200-bed Christian Missionary Hospital, which has been operating in Tank since 1945.

“All of us are safe,” a Finnish staff member who gave her name as Pajari told AFP.

“They put the explosive in our drainage system. It was a noisy explosion but nobody was hurt.”

Local police officer Mohammad Khan told AFP by telephone that similar devices were made in the tribal area bordering Afghanistan.

An investigation was under way to track down the perpetrators, he said.