US Secretary of State Antony Blinken was set to leave for Israel on Wednesday on a Middle East mission to prevent a wider war from erupting after an attack and hostage-taking by Palestinian Hamas militants and an Israeli bombardment of the Gaza Strip.
In a show of solidarity with Washington's closest Middle East ally, Blinken was due to meet senior Israeli officials, possibly including Prime Minister Benjamin Netanyahu, to discuss further boosting military support.
He will work with regional US allies to try to secure the release of more than 100 people that Israel says Hamas holds captive, some of whom may be American citizens.
Blinken, the US top diplomat, was flying out as Israel was forming an emergency unity government. The US State Department did not immediately respond to a request for comment.
Hamas gunmen rampaged through Israeli towns over the weekend, killing 1,200 people and taking scores of hostages to Gaza. Israel has retaliated with air strikes that have killed more than 1,000 people in Hamas-ruled Gaza as it prepares for a possible ground offensive.
At least 14 Americans were killed during the attack by Hamas on Saturday, President Joe Biden said on Tuesday.
A top priority for Blinken will be to convey a message of deterrence, largely aimed at Iran and Iran-backed groups such as Lebanon's Hezbollah, to stop a wider war from erupting.
Hezbollah has moved carefully since Hamas and Israel went to war, keeping Israeli troops busy with attacks at the Lebanese border but not opening a big front, sources familiar with its thinking say.
"Secretary Blinken has been intensely focused on standing with Israel, making clear that parties hostile to Israel should not take advantage of this situation, and working for the release of all hostages held in Gaza," said State Department spokesperson Matthew Miller.
Violence on the border between Israel and Lebanon flared up for a fourth day on Wednesday with Israeli shelling hitting southern Lebanese towns in response to a fresh rocket attack by Iran-backed Hezbollah.
Since Saturday, Blinken has spoken on the phone with his counterparts from Egypt, Jordan, Saudi Arabia, Qatar, Türkiye and the United Arab Emirates. US officials said Washington was pushing regional countries with influence on Hamas and others hostile to Israel to help stop the conflict from worsening.
"The attack by Hamas is a reminder of the perception of an American absence or lack of commitment to the region that some actors might interpret and do things they should not be doing," Alex Vatanka, director of the Iran program at the Middle East Institute said.
Biden on Wednesday called the Hamas attack "sheer evil", reaffirmed US support for Israel and issued an apparent warning to Iran and Iran-backed groups against exploiting the conflict: "I have one word: Don't."
Blinken's trip announcement did not include the Israeli-occupied West Bank. On previous trips to the region, Blinken has visited the West Bank, controlled by the Palestinian Authority and its President Mahmoud Abbas.
Israel has also tightened its siege in Gaza, which it has kept under a blockade since Hamas seized power there in 2007, saying it will keep out food and fuel while vowing to further escalate with a ground offensive.
Washington said it was talking with Israel and Egypt about the idea of safe passage for civilians from Gaza, another key topic that Blinken may be discussing with his counterparts during the trip.
Biden has stopped short of an overt plea to Israel to show restraint to avoid Palestinian civilian casualties in Gaza. It was unclear whether Blinken might make such an appeal when he meets Israeli officials behind closed doors.
