Americans are among the hostages taken into Gaza by Hamas, Israeli Ambassador to the U.S. Michael Herzog confirmed Sunday.

“I understand there, but I don’t have details,” Herzog said during an interview on CBS’ “Face the Nation.”

Hamas, the Islamist militant group that controls the Gaza Strip, launched an unprecedented attack on Israel early Saturday morning, killing hundreds and kidnapping others. The massive incursion came a day after Israel marked the 50th anniversary of the surprise invasion on Yom Kippur, up until now the worst surprise attacks Israel has been subject to.