Four Israeli soldiers have been wounded in a landmine explosion inside Lebanese territory, the Lebanese army says.

The incursion occurred just after 12:00am local time on Wednesday (21:00 GMT on Tuesday) near the town of al-Labouneh in southern Lebanon, the military said in a statement.

The Israeli soldiers crossed the Blue Line border on foot and crossed "roughly 400m inside Lebanon", the statement said.

A Lebanese army intelligence official told Al Jazeera that a landmine then exploded, injuring the four soldiers.

The Lebanese military said that it is investigating the incident.

Adnan Mansour, the caretaker foreign minister, condemned the alleged Israeli incursion in a statement and promised to raise the issue with the United Nations Security Council.

The "Blue Line" is the border between Lebanon and Israel demarcated by the UN in 2000 following the withdrawal of Israeli troops from most of southern Lebanon.

The Israeli military said on Wednesday that the soldiers were hurt during "overnight activity adjacent to the northern border". The soldiers have been admitted to a hospital.

Israeli public radio said the four injured soldiers were part of a special forces unit, and that army reinforcements were deployed to the border after the blast.

On Wednesday morning, Israeli Prime Minister Binyamin Netanyahu confirmed that soldiers had been wounded, adding that the country "will continue to react to defend Israel's border".

Lebanon’s National News Agency reported the explosion occurred because of a landmine and that the Israeli patrol had crossed 150m inside the Lebanese territory.

Asked about the incident, Andrea Teneti, a spokesman for the United Nations Interim Force in Lebanon (UNIFIL), said he had "no information in relation to our mandate of operations" and described the situation as calm.

Local residents reported overnight a flurry of Israeli activity in the sky over south Lebanon and said several light flares from Israeli helicopters were thrown.

Source: Al Jazeera and agencies