(The Hill) — Secretary of State Antony Blinken announced Thursday that at least 25 Americans were confirmed to be killed in the attacks on Israel by Hamas, a Palestinian militant group.

“Tragically, the number of innocent lives claimed by Hamas’s heinous attacks continues to rise,” Blinken said during a press conference in Israel, standing alongside Prime Minister Benjamin Netanyahu. “Among those, we now know that at least 25 American citizens were killed.”

“We joined families in Israel in the United States around the world in mourning their immeasurable loss,” he added.

U.S. officials have been working with Israelis to secure the release of hostages and Blinken noted he will continue to engage in diplomacy in his meetings throughout the region.

Military support from the U.S. has already arrived in Israel, he confirmed, pledging to continue adapting it to the needs of Israel.

“As Israel’s defense needs evolve, we will work with Congress to make sure that they’re met,” he told Netanyahu. “And I can tell you, there is overwhelming, overwhelming bipartisan support in our Congress for Israel’s security.”

His comments come one day after Netanyahu reached an agreement with opposition leader Benny Gantz to form a unity government — which Blinken said the U.S. welcomes.

He also reiterated President Biden’s message of unwavering support for Israel and echoed the president’s warning to neighboring nations.

“We will reaffirm the crystal-clear warning the President Biden issued yesterday to any adversary, state or non state, thinking of taking advantage of the current crisis to attack Israel: Don’t,” he said. “The United States has Israel’s back.”

Blinken delivered a personal appeal, noting his background as a Jew with family that fled pogroms in Europe and survived the Holocaust. 

“I come before you, not only as the United States Secretary of State, but also as a Jew,” he said during the press conference. “My grandfather, Maurice Blinken fled pogroms in Russia. My stepfather, Samuel Pisar, survived concentration camps: Auschwitz, Dachau, Majdanek. So, Prime Minister, I understand, on a personal level, the harrowing echoes that Hamas’s massacres carry for Israeli Jews, indeed, for Jews everywhere.”

“I also come before you as a husband and father of young children. It’s impossible for me to look at the photos of families killed and not think of my own children,” Blinken continued. “This was just one of Hamas’s countless acts of terror.”

The secretary made the trip overseas less than a week after Hamas launched a surprise attack on Israel, brutalizing Israelis and attacking from the sea, air, and by foot. Israel has responded with a barrage of airstrikes. 

More than 1,200 Israelis and 1,350 Palestinians have been killed since Saturday’s initial attack. More than 100 Israelis are also estimated to be held hostage in Gaza.