A tunnel was found on the eastern part of the border between Israel and Lebanon and led onto Israeli territory, said the army, which dubbed the operation Northern Shield. It did not say how far inland the tunnel led.
The tunnels were a "flagrant and severe violation of Israeli sovereignty," Manelis said.
Hezbollah, he added, "continues its activity that is supported and funded by Iran, to establish its terror infrastructure against Israeli civilians."
In Lebanon, the United Nations Interim Forces in Southern Lebanon (UNIFIL), which monitors the situation at the border between the two countries, said the situation remains "calm."
"UNIFIL is liaising with all relevant interlocutors to ensure that the parties use the UNIFIL liaison and coordination mechanisms to maintain the continued calm and stability," spokesperson Malene Jensen told dpa.
The Lebanese army said it was ready "to confront any emergency" on the border.
"In light of the Israeli enemy's announcement at dawn of launching Northern Shield against alleged tunnels on the southern border, the Lebanese army command confirms that the situation on the Lebanese side is quiet ... and it's being monitored closely," the army statement said.
Hezbollah has launched attacks from Lebanon against Israel in the past, often with the support of Iran.
The United States classifies Hezbollah as a terrorist organization, while the European Union uses the terrorist label solely for the group's military wing.
Israel is currently constructing a barrier along the border to Lebanon, in order to protect the country from Hezbollah attacks. The nine-metre-high construction is set to be finished along the 130-kilometre-long border in the next two years.
The tunnels were a "flagrant and severe violation of Israeli sovereignty," Manelis said.
Hezbollah, he added, "continues its activity that is supported and funded by Iran, to establish its terror infrastructure against Israeli civilians."
In Lebanon, the United Nations Interim Forces in Southern Lebanon (UNIFIL), which monitors the situation at the border between the two countries, said the situation remains "calm."
"UNIFIL is liaising with all relevant interlocutors to ensure that the parties use the UNIFIL liaison and coordination mechanisms to maintain the continued calm and stability," spokesperson Malene Jensen told dpa.
The Lebanese army said it was ready "to confront any emergency" on the border.
"In light of the Israeli enemy's announcement at dawn of launching Northern Shield against alleged tunnels on the southern border, the Lebanese army command confirms that the situation on the Lebanese side is quiet ... and it's being monitored closely," the army statement said.
Hezbollah has launched attacks from Lebanon against Israel in the past, often with the support of Iran.
The United States classifies Hezbollah as a terrorist organization, while the European Union uses the terrorist label solely for the group's military wing.
Israel is currently constructing a barrier along the border to Lebanon, in order to protect the country from Hezbollah attacks. The nine-metre-high construction is set to be finished along the 130-kilometre-long border in the next two years.