Hezbollah targeted an Israeli drone over south Lebanon with "appropriate weapons... forcing it to leave" the group said on Thursday.
The announcement came shortly after the Israeli military said an unmanned aircraft had been targeted with anti-aircraft missiles but was undamaged.
The incident is a dramatic escalation of the decades-long conflict between Hezbollah and Israel.
On Thursday afternoon, Israeli military tweeted a short statement, saying, “A short while ago, an anti-aircraft missile was launched over Lebanese territory towards an [Israeli] UAV. The UAV was not hit.”
It gave no further information.
The Lebanese state-run National News Agency reported an explosion was heard over Nabatieh and local media on the scene spoke to residents who also said they heard a loud bang as Israeli planes flew over the area.
Hezbollah affiliated Al Mayadeen TV said the drone was downed.
Israel violates Lebanese airspace on a near-daily basis to carry out surveillance and reconnaissance. Neither Hezbollah nor the Lebanese army usually challenges these militarily but complaints have been lodged with the United Nations.
However, after a cross-border flair up in September, Hezbollah leader Hassan Nasrallah said that the group would start to target Israeli aircraft and drones. Until now, they have not done so.
If the incident is confirmed it would mark an escalation in the long-running conflict between Hezbollah and Israel. It is not clear if the Iran-backed group has ever previously targeted Israeli warplanes in Lebanon with anti-aircraft missiles, even during the last major war between the two in 2006.
A local resident posted an unverified video claiming to show the missile trails on social media. While it is not clear if the footage depicts the event described by the Israeli military, it appears to show the white snaking trail left after a missile is launched raising up from the hillside in an area that appears to be south Lebanon.
There has been no confirmation from the Lebanese authorities and no further information from Israel.
In August, two Hezbollah fighters were killed in an Israeli airstrike in Syria.
Then, on August 25, two Israeli drones crash-landed in Beirut. One of the craft blew up, damaging a Hezbollah media centre.
A day after, Israel struck an encampment of the pro-Syrian Popular Front for the Liberation of Palestine-General Command militia.
Hezbollah responded a few days later by firing two anti-tank missiles at an Israeli armoured car. While they claimed to have caused casualties, the Israeli authorities denied that anyone had been wounded.
Israel responded by shelling around the area the missiles had been launched from but the situation quickly stabilised.
Then prime minister of Lebanese, Saad Hariri, described the drone incident over Beirut as an “open attack on the country's sovereignty.”
More to follow...