Lebanese Prime Minister Hassan Diab called for caution and accused Israel of violating Lebanon’s sovereignty following a reported clash between Israel and Hezbollah on Monday. Israel-Hezbollah tensions are high following the death of a Hezbollah fighter in Syria last week.

“Israel violated Lebanon’s sovereignty once again,” Diab said in a tweet Tuesday. “I call for caution in the coming days.”

The Israel Defense Forces (IDF) said a group of Hezbollah fighters crossed a few feet into Israeli territory on Monday. The IDF said it thwarted the attack with gunfire and tank shelling. Hezbollah denied launching an attack into Israel.

A militant group and political party, Hezbollah formed in the 1980s in part to fight the Israeli military, which controlled parts of southern Lebanon at the time. It receives considerable military and political support from Iran. Hezbollah and Israel fought each other in the 2006 Lebanon War and have since clashed now and again. The group controls large parts of Lebanon and is part of the government. Like Iran, Hezbollah also fights in Syria alongside the Syrian government.