"We announce that we have lost contact with the group holding soldier Edan Alexander following a direct strike on their location. We are still trying to reach them at this moment," Abu Obeida, spokesman for the Ezzedine Al-Qassam Brigades, said on his Telegram channel.

The Brigades released a video on Saturday showing Alexander alive, in which he criticised the Israeli government for failing to secure his release.

Alexander appeared to be speaking under duress in the video, making frequent hand gestures as he criticised Prime Minister Benjamin Netanyahu's government.

AFP was unable to determine when the video was filmed.

Alexander was serving as a soldier in an elite infantry unit on the Gaza border when he was abducted by Palestinian militants during their October 7, 2023 attack on Israel.

The soldier, who turned 21 in captivity, was born in Tel Aviv and grew up in the US state of New Jersey, returning to Israel after high school to join the army.

Out of the 251 hostages taken on October 7, 58 remain in captivity, including 34 whom the Israeli military says are dead.

Nearly a month after Israel resumed its aerial and ground assaults across Gaza, the Palestinian militant group said on Monday it had received a new ceasefire proposal from Israel.

A senior Hamas official told AFP that Israel had proposed a 45-day ceasefire in exchange for the release of 10 living hostages.

The Hamas official said that the Israeli proposal calls for the release of Alexander on the first day of the ceasefire as a "gesture of goodwill".