By the CNN Wire Staff
An Egyptian military delegation visiting Washington abruptly canceled meetings with senior American lawmakers and returned to Egypt, Sen. John McCain told CNN Tuesday.
McCain, the ranking Republican on the Senate Armed Services Committee, did not give a reason why the Egyptians backed out.
U.S. aid to Egypt hangs in the balance amid Egypt's decision to prosecute 43 people, including 19 Americans, in a crackdown on civil society organizations.
"We have underscored how serious a problem these actions are. We have said clearly that these actions could have consequences for our relationship, including regarding our assistance programs," White House spokesman Jay Carney told reporters Monday.
State Department spokeswoman Victoria Nuland reiterated the message moments later in a separate briefing. She declined to speculate about possible consequences but said the dispute "is a very, very difficult situation in terms of the support we want to provide Egypt."
The United States sends more than $1.3 billion each year in military aid to Egypt, according to the U.S. State Department. Since 1975, the U.S. Agency for International Development has provided more than $28 billion in economic and development assistance to the country.
Egyptian authorities carried out 17 raids on the offices of 10 nongovernmental organizations in December. A spokesman with the general prosecutor's office said the raids were part of an investigation into allegations that the groups had received illegal foreign financing and were operating without a proper license.
Three U.S.-based organizations were part of the raids.
Among the 19 Americans referred to a court for prosecution is Sam LaHood, International Republican Institute country director and the son of U.S. Transportation Secretary Ray LaHood, according to Adel Saeed, a spokesman for the general prosecutor.
Some of those facing charges have taken shelter at the U.S. Embassy in Cairo, Nuland said.
"The number has grown slightly," she said, declining to provide additional details.
The groups targeted have operated in Egypt for years, and none funded candidates or parties, Nuland said.
"There is nothing new in their activities," she said.
President Barack Obama has spoken to Field Marshal Mohamed Tantawi, head of Egypt's ruling military council, about the issue, and Defense Secretary Leon Panetta and U.S. Ambassador Anne Patterson have also spoken with high-ranking Egyptian officials to voice their concern, U.S. officials have said.
"You can be sure we are engaging with the Egyptian government on this issue at every level," Carney said Monday.
CNN's Ted Barrett contributed to this report.