Secretary of State Antony Blinken said Sunday the US is "working overtime" to verify reports of missing and dead Americans overseas after Hamas launched an unprecedented attack against Israel.
"We have reports that several Americans were killed. We're working overtime to verify that. At the same time, there are reports of missing Americans and there again, we're working to verify those reports," Blinken told CNN's Dana Bash on "State of the Union."
The large-scale surprise attack by Gaza militants on Israel on Saturday has left hundreds of Israelis dead, prompting vows of retribution from Israeli Prime Minister Benjamin Netanyahu and a lethal volley of retaliatory Israeli airstrikes.
It's unclear what Israel's full response will look like. An Israeli military spokesperson hinted that Israel may try to take full control of Gaza for the first time since 2005, and more than 20 communities near Gaza are being evacuated.
Blinken said an announcement on additional aid to Israel in response to the attack could be announced as soon as Sunday.
"We're looking at specific additional requests that the Israelis have made -- I think you're likely to hear more about that later today," Blinken said.
The top US diplomat added that President Joe Biden's direction was to "make sure that we're providing Israel everything it needs in this moment to deal with the attacks from Hamas."
Speaking from the White House Saturday, Biden said his administration's support of Israel's security is "rock solid and unwavering."
"When I spoke with Prime Minister Netanyahu this morning, I told him the United States stands with the people of Israel in the face of these terrorist assaults. Israel has the right to defend itself and its people, full stop," he said.
Still, the president and his top aides are contending with a complicated diplomatic situation unlike any previous conflict between the Israelis and the Palestinians.
Republican presidential candidates have slammed the Biden administration, with former President Donald Trump -- the front-runner for the GOP nomination -- pointing to the administration's unfreezing of Iranian funds to claim that Biden "betrayed Israel."
Blinken, however, reiterated on Sunday that no money has been spent from the unfrozen funds intended for humanitarian purposes.
"So people are either misinformed or they're misinforming," he said. "And either way, it's wrong."
This story has been updated with additional information.