Republican congressman Ron Paul says the US is aiding and abetting Israel in Gaza through its financial and military support for Tel Aviv.
"The weapons being used to kill so many Palestinians are American weapons, and American funds, essentially, are being used for this," said the congressman Friday.
Israel launched an all-out war against the Gaza Strip and its democratically-elected ruler, the Hamas movement, to put an end to rocket attacks against southern Israel.
At least 821 Palestinians have been killed during the operation and some 3,330 others are reported wounded. At least 10 Israeli troops have been killed during the offensive so far.
Hamas demands a cessation to an 18-month Israeli blockade on Gaza before its fighters stop rocket attacks against Israel.
Congressman Paul criticized Washington for its indirect intervention in the affairs of other countries.
"There's a political liability, which I think is something that we fail to look at, because too often there's so much blowback from our intervention in areas that we shouldn't be involved in," he said.
Paul also expressed his opposition to a House resolution that strongly supported Israel in its Gaza invasion. "I rise in opposition to this resolution, not because I am taking sides and picking who the bad guys are and who the good guys are."
"I'm looking at this more from the angle of being a United States citizen, an American, and I think resolutions like this really do us great harm," he added.
Earlier on Friday, House of Representative speaker Nancy Pelosi backed the Israel's military operations on Gaza, saying that "Israel, like any nation, has a right to self-defense when under attack".
"There's a lot of reasons why we should oppose this resolution. It is not in the interests of the United States. It's not in the interests of Israel, either," Paul concluded.
The fighting in Gaza has entered its third week despite a UN Security Council resolution which calls for an immediate end to the hostility in the densely-populated Gaza Strip.