The Israeli government opposes the creation of a Palestinian state and seems willing to take additional action to block the possibility, such as annexing at least some of the land envisioned for it. “A Palestinian state will not be established west of the Jordan River,” Prime Minister Benjamin Netanyahu of Israel said on Sunday. He said it would exclude Hamas, the Palestinian militant group that long ruled Gaza and led the 2023 attack on Israel that set off the Gaza war. Speaking via video link because the United States denied him a visa to participate in the summit in New York, Mr. Abbas addressed the people of Israel directly. A Palestinian state cannot be created unilaterally without the agreement of Israel, which largely controls both the West Bank and Gaza and the millions of Palestinians who live in those territories.