Israeli troops have captured a strategic mountain topped with a Crusader-built castle in southern Lebanon in their deepest incursion into the country in 26 years, the military says.The capture of Beaufort castle near the city of Nabatiyeh came after days of intense fighting and air strikes in nearby villages where Israeli troops fought Hezbollah members in the rugged area.It marks a major gain for Israel in the latest Israel-Hezbollah war, which began in early March.Israel and Lebanon have been at war since Israel was created in 1948, and are currently holding direct talks in Washington.The Israeli push came despite a nominal ceasefire that has been in place since April 17 and just days before the next round of talks are set to be held at the US State Department in Washington on June 2 and 3.The Israeli army's Arabic spokesperson, Avichay Adraee, posted a photo on X showing Israeli troops walking outside the castle, and Defense Minister Israel Katz wrote on X that they had raised an Israeli flag over the castle.The Israeli capture of the castle and strategic ridge is a major advance against Iran-backed Hezbollah. (Supplied: X/Avichay Adraee)Israeli troops previously captured the castle in 1982 and held it until they withdrew from Lebanon in 2000.The advance has granted Israeli troops an overlook point over much of southern Lebanon and northern Israel, from which attacks have been launched towards Israeli residential areas.The Israeli military said in a statement that it launched an operation a few days ago in the Beaufort Ridge and the Suluki valley further south with the aim of dismantling Hezbollah infrastructure and removing "direct threats to Israeli civilians".The statement said the army is ready "to expand the operation if needed".In recent days, Israel has expanded the scope of its operations in Lebanon, sending troops across the Litani River, which previously served as a de facto boundary, and demanding that residents leave much of southern Lebanon.Israel has designated the area from the Litani up to the Zahrani River a combat zone. Some residents have already left due to the intense strikes in recent days, but people remain in many of the area's towns.Israeli troops are now about 5 kilometres from the city of Nabatiyeh, a major centre in southern Lebanon, and have called on all its residents to leave, as well as the residents of the coastal city of Tyre, the country's fourth largest city, and its surroundings.There was no immediate comment from Hezbollah or the Lebanese government on the Israeli push.Israeli troops have raised the Israeli flag (right) and the Golani flag, representing the 1982 capture, over the castle. (Supplied: X/Israel Katz)Hezbollah overnight claimed two attacks targeting Israeli troops and a Merkava tank in the south-western town of Bayada near the border.In recent days, the group has said it has clashed with Israeli troops in several towns just north of the river near Nabatiyeh and the strategic castle.Hezbollah in recent weeks has frustrated Israel with attacks on troops and northern towns using hard-to-detect fibre optic drones.The latest Israel-Hezbollah war began on March 2, when Hezbollah fired rockets into northern Israel two days after the US and Israel attacked its main backer, Iran.Israel has since launched a ground invasion, capturing dozens of Lebanese villages and towns close to the border.It has left 3,350 people dead in Lebanon and more than 1 million people displaced.According to Israeli Prime Minister Benjamin Netanyahu's office, at least 25 Israeli soldiers and a defence contractor have been killed in or near southern Lebanon and two civilians have been killed in northern Israel, the vast majority by drones.AP/Reuters