CAIRO — Egyptian investigators filed criminal charges Sunday against at least 40 international civil society workers, reportedly including the son of a U.S. Cabinet secretary, in a controversial case that could cost the ruling generals millions of dollars in U.S. aid.

Nineteen Americans are among the employees of nongovernmental organizations, or NGOs, referred to trial on charges of involvement in banned activities and receiving foreign funds illegally, according to state media. The other defendants are Egyptians, Serbs, Germans and Arabs from other countries, according to news reports. All of them face a travel ban preventing them from leaving Egypt.

The highly politicized case, which has drawn outrage from Egypt's once-close allies in Washington, shows that the ruling Supreme Council of the Armed Force is willing to risk Egypt's annual $1.3 billion in U.S. military aid to assert sovereignty and win some points at home, analysts said.

"SCAF wants to demonstrate its anti-American credentials," said Robert Springborg, a professor at the Naval Postgraduate School who's written extensively on the Egyptian military.

In Egypt, a cross-section of political elites have long resented the NGOs' work here on the belief that they were imposing Western values on a deeply conservative Arab Muslim nation.

For years, American and Egyptian nonprofit workers say, authorities have blocked them from full registration and smeared them in state media as foreign provocateurs trying to destabilize Egypt.

On Dec. 29, Egyptian authorities raided the offices of 17 NGOs, including the U.S.-based International Republican Institute, Freedom House and National Democratic Institute. The groups receive U.S. government funding and were conducting candidate training and other activities related to the Egyptian parliamentary elections.

Helmy el Rawy, head of an Egyptian human rights NGO that was raided and which has one member under investigation, said the case was purely political, with evidence so deliberately weak that no court would accept it as sufficient. He interprets the generals' strategy as: Try the Americans, win public support; then acquit the Americans, mend relations with Washington.

"We all know these NGOs have been functioning in Egypt for five years, with or without licenses, and the Egyptian officials knew about it. Some even dealt with them," Rawy said.

Included in those reportedly referred Sunday for trial is Sam LaHood, the son of U.S. Transportation Secretary Ray LaHood and head of Egypt programming for the International Republican Institute.

An International Republican Institute official, speaking on condition of anonymity because of the sensitivity of the matter, said the group only heard about the charges through Egyptian media and hadn't yet confirmed the development independently. By the time lawyers went to the high court to check late Sunday afternoon, the official said, the offices were closed.

U.S. officials have acknowledged that International Republican Institute employees were among a handful of suspects granted extraordinary permission to take refuge at the American Embassy in Cairo, ostensibly putting them out of risk of arrest.

On Sunday, the Egyptian state news service MENA reported that investigating judges ordered that "the suspects be brought to Cairo Criminal Court for trial." The International Republican Institute official said the group hadn't yet decided whether to cooperate with a proceeding it considers as part of a witch hunt against pro-democracy activism.