The United States on Monday acknowledged there have been "thousands" of civilian casualties in Gaza as Israel battles Hamas in the narrow coastal territory, but did not provide an exact figure.

Israel's military responded to a Hamas attack that killed 1,400 people earlier this month with a relentless air, land and naval assault on Gaza that the territory's health ministry said Monday has left more than 10,000 people dead.

"As it relates to civilian casualties in Gaza... we know the numbers are in the thousands," Pentagon spokesman Brigadier General Pat Ryder told journalists when asked about the health ministry's toll in Hamas-run Gaza.

"This is a reason why it has been a point of emphasis with the Israelis and others in the region on how important it is to get humanitarian assistance and aid into Gaza," Ryder said.

The validity of the numbers published by the Gaza health ministry have been called into question by US President Joe Biden, who has been steadfast in supporting Israel and opposing a ceasefire.

The United States responded to the October 7 Hamas attack by rushing military assistance to Israel and bolstering its forces in the region, including with two carrier strike groups.

Washington's forces in the Middle East have come under repeated attack in recent weeks, with the United States blaming Iran-backed militias for the violence.