Nearly a day after the detention of former US lawmaker Cynthia McKinney by Israeli forces, Washington has yet to make a reaction.

Israeli Navy detained former US congresswoman and Nobel Prize laureate Cynthia McKinney and twenty other human rights activists on board a relief boat outside Israel's territorial waters on Tuesday as they were heading to Gaza on a humanitarian mission.

Tel Aviv claims the boat was trying to break Israel's two-year siege on Gaza.

Ms McKinney -- the 2008 Green Party nominee for President of the United States-- has accused Tel Aviv of violating the international law by seizing an aid vessel in international waters.

"This is an outrageous violation of international law against us. Our boat was not in Israeli waters, and we were on a human rights mission to the Gaza Strip," McKinney said in a statement.

Green Party leaders have called on the White House and the US State Department to intervene and demand the immediate release of all the activists.

On Monday, the International Committee of the Red Cross warned of dire humanitarian situation in Gaza, saying 1.5 million Palestinians living in the coastal sliver are 'trapped in despair' because of the continuing Israeli blockade on the territory.

Since June 2007, when Israel imposed a blockade on the territory, no raw material has entered Gaza, stalling any attempt to rebuild the strip.

According to the humanitarian agency report, seriously ill patients were not receiving the treatment they needed and thousands of Gazans whose homes were destroyed during Israel's three-week Christmas war were still without shelter.