An explosion aboard a bus in Israel on Sunday that did not kill or wound anyone was a "terrorist attack," police said.

"After examining the explosives retrieved from the scene, we have concluded that this was a terrorist attack," police spokesman Micky Rosenfeld told AFP.

Police had earlier said that a sapper had been called to examine a suspicious object found on an empty bus near Tel Aviv. The expert was examining the object when it exploded, but was not injured.