Former U.S. President Jimmy Carter called the blockade imposed on the Gaza Strip a "crime and an atrocity" on Thursday, and said U.S. attempts to undermine the Islamist movement Hamas had been counterproductive.

Speaking at the American University in Cairo after talks with Hamas leaders from Gaza, Carter said Palestinians in Gaza were being "starved to death", receiving fewer calories a day than people in the poorest parts of Africa.

"It's an atrocity what is being perpetrated as punishment on the people in Gaza.It's a crime... I think it is an abomination that this continues to go on," Carter said.

Israel imposed a blockade on Gaza after the Islamist group Hamas seized power over the impoverished coastal strip last June. Since then, Israel has allowed only basic staples to be transported through the border crossings it controls, into Gaza.