JERUSALEM (AP) — Israeli Prime Minister Benjamin Netanyahu warned the Islamic militant group Hamas that rules Gaza on Sunday that his country will retaliate with “greater force” than deployed in the 2014 Gaza war if cross-border tunnels are used to attack Israel.

Hamas has built a sophisticated network of tunnels to infiltrate Israel in order to carry out attacks. Israelis living near Gaza have reported hearing tunneling sounds under their homes recently.

“We are operating systematically and calmly against all threats, including those from Hamas, both with defensive and offensive means, and of course in the event we are attacked by tunnels in Gaza we will operate with great force against Hamas, with much greater force than what we used in Operation Protective Edge,” Netanyahu said in a speech to diplomats Sunday night, referring to the 50-day war with Gaza gunmen in 2014 by its military name.

“I think that is understood in the region, it’s understood in the world. I hope we won’t need to do it but our abilities both defensive and offensive are developing rapidly, and I wouldn’t recommend anyone to try us,” he said.

A senior Hamas leader boasted on Friday that Gaza militants dig tunnels and test rockets to attack Israel “every day.” Ismail Haniyeh spoke at the funeral of seven militants who died this week when a tunnel from Gaza to Israel collapsed while they were repairing it. He said the tunnels are a “preparation” for war with Israel and boasted Hamas has “has built tunnels two times more than Vietnam tunnels.”

The 2014 Gaza war was sparked by a chain of events stemming from the kidnapping and killing of three Israeli teenagers in the West Bank by Hamas gunmen and the kidnapping of a Palestinian teenager who was killed by Israeli extremists in a revenge attack. Israel arrested hundreds of Hamas members in raids in the West Bank, prompting militant groups in Gaza to escalate rocket attacks on Israeli cities.

Parts of Gaza were devastated in the fighting.

The war also exposed Israeli communities near Gaza to a new threat: underground Hamas attack tunnels that surfaced close to their homes.

Earlier Sunday, a Palestinian opened fire at a West Bank checkpoint and wounded three soldiers before he was shot and killed by troops, the military said.

Palestinians identified the gunman as Amjad Sukkari, a 34-year-old policeman who worked as a bodyguard for the Palestinian attorney general.