Egyptian riot police are firing tear gas canisters bearing the label "Made in U.S.A" against street demonstrations in Cairo, according to protesters who provided ABC News with pictures of the canisters.
The protestors said the tear gas canisters were recovered in Tahrir Square in downtown Cairo on Tuesday.
The label urges anyone who comes in contact with the gas "to seek assistance as soon as possible."
According to the canister labels, the tear gas is produced by Combined Systems International of Jamestown, Pennsylvania.
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The company's web-site says it sells "non-lethal weapons" to foreign governments, without specifying Egypt.
A company spokesperson did not return calls by ABC News seeking comment.
The United States provides $1.3 billion a year in military financing for Egypt. According to the State Department's 2010 budget request, the aid is used to help strengthen and modernize the Egyptian army.
Egyptians who are part of the street demonstrations told ABC News that the evidence of the U.S.-made tear gas sends a powerful signal.
"The way I see it the U.S. administration supports dictators," said Aly Eltayeb, 26, who has participated in the protests since Tuesday.
"The way tear gas works is by spreading panic," he said. "Your eyes tear up a lot so you can't see, and you feel like your suffocating. You can actually breathe but you feel like you are suffocating so you try to run, but when you run you inhale more."
Protestors made the discovery of the U.S. tear canisters at the same time Secretary of State Hillary Clinton and other U.S. officials called for peaceful solutions and restraint by the Egyptian government.
Eltayeb, a graduate student who lives in the Boston, said the protesters see U.S. aid as the key that allowed President Hosni Mubarak to hold power for almost thirty years.
"U.S. political institution as a whole supports dictators in the Middle East as long as they do the torturing for them," he said.
Military aid to Egypt has long been a central element of US policy in the region.
"The effort is to try to fulfill several purposes," said Robert Danin of the Center for Foreign Relations. "It keeps the army strong. Egypt has its own military requirements in the face of threats in the region, Sudan and Libya and at the same time it's a symbol of the confidence that the US has in Egypt."