The United Nations Interim Force in Lebanon (UNIFIL) confirmed on Thursday that a tunnel discovered by Israel earlier this year alongside the Lebanese-Israeli border, dug by the terrorist group Hezbollah, was the third violation of a ceasefire measure.

“UNIFIL’s independent assessment confirms that this tunnel crosses the Blue Line in violation of Resolution 1701,” said the peacekeeping group.

U.N. Resolution 1701 requires all armed groups except the Lebanese Armed Forces—the official Lebanese military—to remain north of the Litani River following the end of the 2006 Second Lebanon War.

“UNIFIL has informed the Lebanese authorities about the violation and has requested urgent follow-up actions,” it stated.

In January, Israel accused Hezbollah, an Iranian proxy with a stronghold in Lebanon, of digging what it labeled as the “longest and most detailed” border tunnel the Jewish state has yet discovered.

The Israel Defense Forces launched “Operation Northern Shield” in December 2018 to destroy Hezbollah terror tunnels, followed by conducting a massive simulation to train troops for combat missions in conditions similar to those in Lebanon.