The U.S. State Department issued a press statement Friday expressing concern over groups planning to participate in an impending flotilla to the Hamas-controlled Gaza Strip. The flotilla, slated to set sail next week, aims to intentionally break Israel's naval blockade of the coastal Strip.

"Groups that seek to break Israel's maritime blockade of Gaza are taking irresponsible and provocative actions that risk the safety of their passengers," the statement reads. It notes that last month was the one year anniversary of last year's Freedom Flotilla, which resulted in the death of nine passengers after activists on the IHH-owned Mavi Marmara ship staged a violent confrontation with Israeli commandos.

"Established and efficient mechanisms exist to transfer humanitarian assistance to Gaza," and the U.S. State Department urges "all those seeking to provide such assistance to the people of Gaza to use these mechanisms, and not to participate in actions like the planned flotilla."

Israel imposed a naval blockade on the Gaza Strip in 2007 to prevent weapons and materials that could be used by Hamas in terrorist attacks from reaching the region. Yet "[r]ecent seizures by Israel and Egypt of advanced military systems, weapons, and ammunition, bound for terrorist groups in Gaza, as well as periodic rocket and mortar attacks from Gaza against Israeli civilians, highlight the continuing problem of illicit arms smuggling to Gaza," according to the State Department.

On Thursday, Secretary of State Hillary Rodham Clinton criticized the planned flotilla, saying it is not "necessary or useful."

A new travel warning for Israel, the West Bank and Gaza was released by the State Department Wednesday. The release warned "against participation in any attempt to reach Gaza by sea."

Despite the State Department's actions, approximately 50 people, including media personnel, are currently in Greece preparing to sail to Gaza on a U.S. flagged ship. The U.S. Boat to Gaza is expected to be accompanied by at least nine other boats from countries around the world. Its organizers have publicly dismissed the government's concerns, and have claimed that they are engaging in "non-violence training" in case of a confrontation with Israel while en route to Gaza.