The office of the mayor of Jerusalem reported that the Monday explosion on an empty bus was caused by a bomb. Sixteen people on a nearby bus were injured in the blast, according to the Jerusalem Post.
A blast aboard a Jerusalem bus that wounded 16 people on Monday was caused by a bomb, a spokeswoman for the Israeli mayor, Nir Barkat, said. "It was small, but it was definitely a bomb," Brachie Sprung told Reuters.
Two of the wounded are listed in critical condition, with the others listed as either in moderate or light condition.
The Jerusalem Post reported that other authorities can not confirm if the explosion was the result of a bombing.
Police said that the cause of the incident was still under investigation but suspicions were mounting that it was a terror attack, according to Channel 2. Police were investigating whether one of the critically injured in the explosion was carrying a small explosive device.
Bus bombings have been a hallmark of Palestinian terror groups, but there has been a decrease in bombings since 2005.
The explosion comes amid a rise in Palestinian knife attacks on Israelis, especially military and police officers. According to Israel's Ministry of Foreign Affairs, 34 people have died in attacks by Palestinians. Another 361 people have been wounded since September 13, 2015, from stabbings, shootings and vehicular ramming attacks.