U.S. Secretary of State Mike Pompeo said on Monday that Hezbollah tunnels from Lebanon to infiltrate and attack Israel “violate the most basic premise of sovereignty.”

“The United States fully supports Israel’s right [to defend themselves from Iranian aggression], and we do our best to support their capability to defend themselves from Iranian aggression,” Pompeo told conservative radio-talk show host Hugh Hewitt. “These tunnels are Iranian-connected Lebanese Hezbollah efforts to violate the most basic premise of sovereignty, of national sovereignty—that is, digging tunnels onto someone’s terrain.”

The Israel Defense Forces launched “Operation Northern Shield” last week to discover and eliminate underground tunnels constructed by Hezbollah from Lebanon to Israel.

“We support Israel’s right to defend itself, including the exercises on the Israeli side of the border that they now are calling ‘Northern Shield,’ ” said Pompeo, who met with Israeli Prime Minister Benjamin Netanyahu in Brussels last week to discuss the Iranian threat and other issues.