Police in Istanbul have launched a "large-scale investigation" after a Palestinian was killed and two others were wounded in a shooting as they sat in a car, officials and media said Monday.

The killer dropped a handgun fitted with a silencer at the scene, the Istanbul Governor's Office said in a brief statement.

A former Saudi official alleged in a report that Saudi Arabia's Crown Prince Mohammed bin Salman forged the signature of his father on the royal decree that launched the kingdom's yearslong, stalemated war against Yemen's Houthi rebels.

Saudi Arabia did not immediately respond to a request for comment over the allegations made without supporting evidence by Saad al-Jabri in an interview published Monday by the BBC, though the kingdom has described him as "a discredited former government official." Al-Jabri, a former Saudi intelligence official who lives in exile in Canada, has been a yearslong dispute with the kingdom as his two children have been imprisoned in case he describes as trying to lure him back to Saudi Arabia.

Top U.S. diplomat Antony Blinken on Monday urged Israel and Hamas not to derail negotiations that he said may be a "last opportunity" to secure a Gaza truce and hostage release deal.

Blinken, on his ninth regional tour since Hamas's October 7 attack triggered the war, said he was back in Tel Aviv "to get this agreement to the line and ultimately over the line."

Palestinian officials said two people were killed in an Israeli air strike in the occupied West Bank on Saturday that the Israeli military said targeted a "terrorist cell" in the Jenin area.

Top U.S. diplomat Antony Blinken headed to Israel on Sunday seeking a Gaza ceasefire deal that could help avert a wider war, while a senior Hamas official dismissed "American diktats" in negotiations.

Making his ninth trip to the Middle East since the Gaza war began with Palestinian militants' October 7 attack, the secretary of state is due to meet Israeli leaders before truce talks resume in Cairo.

U.S. President Joe Biden is aiming to get a Gaza ceasefire and hostage release deal by the end of next week while also trying to deter Iran and Hezbollah from conducting an attack on Israel that could undermine this effort, U.S. officials have told U.S. news portal Axios.

Gaza has recorded its first polio case in 25 years, the Palestinian health ministry said, after U.N. chief Antonio Guterres called for pauses in the Israel-Hamas war to vaccinate hundreds of thousands of children.

A U.S. official warned that Iran would face "cataclysmic" consequences and derail momentum toward a Gaza truce if it strikes Israel in response to the killing of a top Hamas official.

Hamas said it rejected "new conditions" in a Gaza ceasefire proposal that U.S.-led mediators presented during two days of talks in Qatar.

Israeli Foreign Minister Israel Katz told his French and British counterparts Friday that Israel expects support "in attacking" Iran if it strikes Israeli territory.

"If Iran attacks, we expect the coalition to join Israel not only in defense but also in attacking significant targets in Iran," Katz told his French and UK counterparts during their visit to Israel.