A Chicago-born man arrested as the suspect in the fatal shooting of two Israeli embassy employees in Washington DC was charged on Thursday in US federal court with two counts of first-degree murder, Reuters reports.

Elias Rodriguez, 31, is accused of opening fire on a group of people on Wednesday night as they left an event for young professionals and diplomats hosted by the American Jewish Committee, an advocacy group that fights antisemitism and supports Israel.

Rodriguez told police on the scene, "I did it for Palestine, I did it for Gaza," according to the charging documents.

The two victims struck by gunfire and killed were identified as Yaron Lischinsky, 30, and Sarah Lynn Milgrim, 26, a young couple about to become engaged to be married.

US Attorney General Pam Bondi said earlier that the suspect was believed to have acted alone.