United Nations Secretary-General Antonio Guterres warned on Sunday that any attacks against peacekeepers "may constitute a war crime," his spokesperson said after Israeli tanks burst through the gates of a peacekeeping base in southern Lebanon.

It was the latest accusation of Israeli violations and attacks against the U.N. peacekeeping mission, known as UNIFIL, in recent days.

"UNIFIL peacekeepers remain in all positions and the UN flag continues to fly," U.N. spokesperson Stephane Dujarric said in a statement.

"The Secretary-General reiterates that UNIFIL personnel and its premises must never be targeted. Attacks against peacekeepers are in breach of international law, including international humanitarian law. They may constitute a war crime," he said.