Israel has introduced what it said was a new U.S. ceasefire plan and is trying to force Hamas to accept it by imposing a siege on the Gaza Strip.

Israel's Prime Minister Benjamin Netanyahu threatened Hamas on Monday with unimaginable consequences if it did not return hostages held in Gaza, while the Palestinian group accused his government of sabotaging the truce.

As the first phase of the truce in Gaza ends, the two sides are continuing negotiations but also preparing for a possible return to war.