The trial of dozens of democracy activists, including 16 Americans, has opened in the Egyptian capital.

The Americans are among 43 people who are accused of receiving illegal funds from abroad and carrying out political activities unrelated to their civil society work.

Witnesses say at least 13 of the defendants appeared in court Sunday in Cairo, but it is unclear if any of the Americans were there. Some of the accused Americans have already left Egypt, and others still in the country have taken refuge at the U.S. Embassy in Cairo.

The case has raised already high tensions between the United States and Egypt, and it comes as the U.S. is trying to establish better ties with the military council that took power last year following the ousting of former president Hosni Mubarak.

U.S. officials say the Obama administration has been in “intense discussions” with Egypt to resolve the issue.

Among the Americans accused is Sam LaHood, Egypt director of the International Republican Institute and son of U.S. Transportation Secretary Ray LaHood.

The remaining suspects include Germans, Palestinians, Jordanians and Egyptians.

The United States has warned that going forward with the trial could prompt a cut to Cairo's $1.3 billion in annual U.S. military aid.