The Lebanese army says troops have advanced along the border with Syria, tightening the siege on areas controlled by the Islamic State group.

The army said in a statement Tuesday that the troops discovered bombs and explosive belts left behind by militants in areas captured on the edge of the Lebanese border town of Arsal.

It said that they also found the body of an unknown man.

The Lebanese army has been preparing for an all-out attack on IS positions along the Syrian border for weeks, massing reinforcements and pounding the area with artillery shells and rockets.

The Syrian army and Hezbollah are preparing for a simultaneous attack on the Syrian side of the border.