At least five people were killed in a shooting attack at a bus station in Jerusalem on Monday, the Israeli emergency service Magen David Adom (MDA) reported.

Another 15 people were injured, three of them seriously, according to Eli Bin, MDA’s director-general. Israeli Channel 12 reported that gunmen boarded a bus and opened fire on passengers.

The identity of the shooters and their motive remain unclear. Israeli police described the attackers as “terrorists” but did not provide details on the number of perpetrators, though some reports indicate there were at least two.

Israeli media said the assailants used an improvised submachine gun, known as a “Carlo” or Carl Gustav, in the deadly attack in the Ramot neighborhood. These homemade firearms are typically produced in illegal workshops in the West Bank and have been used in numerous Palestinian attacks in the past.

Both gunmen were shot and “neutralized” at the scene. Their identities and conditions are not immediately known, though there are indications—beyond the type of weapon used—that the attackers may have come from the West Bank.

If confirmed, this could further escalate Israeli pressure on the region, which the Netanyahu government has openly discussed annexing.

BBC reported that Prime Minister Benjamin Netanyahu reviewed the situation with senior security officials in the aftermath of the attack, according to his office.

Hamas lauded what it described as a “heroic and exceptional operation carried out by two Palestinian resistance fighters,” calling it a “natural response to the crimes of the Israeli occupation and the genocide being perpetrated against our people.”