As Israel pounded northern Gaza with air strikes last October and ordered the evacuation of more than a million Palestinians from the area, a senior Pentagon official delivered a blunt warning to the White House.

The mass evacuation would be a humanitarian disaster and could violate international law, leading to war crime charges against Israel, Dana Stroul, then the U.S. deputy assistant secretary of defense for the Middle East, wrote in an Oct. 13 email to senior aides of President Joe Biden. Stroul was relaying an assessment by the International Committee of the Red Cross that had left her "chilled to the bone,” she wrote.

As the Gaza war nears its first anniversary and the Middle East teeters on the brink of a wider war, Stroul’s email and other previously unreported communications show the Biden administration’s struggle to balance internal concerns over rising deaths in Gaza with its public support for Jerusalem following the Hamas attack on southern Israel on Oct. 7 that killed 1,200 people.