The Israeli army is concerned about a possible Lebanese plan to divert a crucial river whose downstream runs through the Jewish country, local media reported on Monday.

The Hatzbani, which runs through both countries' territories, has been a source of conflicts over the years, and Israel has warned that any changes in its flow would constitute a casus belli.

Israel's recent concerns, according to a Monday report by The Jerusalem Post, stem from a Lebanese plan to build a large tourism center on their part of the river, not far from a northern Israeli border town.

The river provides 25 percent of the Jordan River's flow, which marks part of Israel's eastern border with the Hashemite Kingdom. In the past, conflicts have broken out between Lebanon and Israel over the issue of diverting several rivers that supply much of Israel's water.

A senior Israel Defense Forces (IDF) officer said that the center's construction needed to be closely tracked due to the possibility that it included diverting the Hatzbani.

"It has our attention and we are keeping a close eye on what is happening there," the officer said. "Our concerns range from the diversion of water to the possibility that the tourism center will be used as a cover to launch attacks against Israel."

Although there has not been actual fighting between the sides since the 2006 conflict, tensions along the border still run high.

In a recent incident, Israeli soldiers patroling the border near the river spotted Lebanese troops 20 meters away, aiming weapons at them, including a rocket-propelled grenade.

An Arabic-speaking Israeli soldier reportedly heard the Lebanese commander instructing his men as to where to aim at the IDF troops.

Israel has informed UNIFIL of the incident, and plans to raise the issue at one of the upcoming tripartite meetings with the multi-national peacekeeping force and Lebanese army representatives.

"This could become a strategic problem," another officer said.

In 2001, Israel threatened Lebanon with military action if it continued to allow villagers to divert the Hatzbani's waters. Then- prime minister Ariel Sharon warned Lebanon that diversion of the waters would be viewed as a "pretext for war."