The United States is considering designating the Red Sea state of Eritrea a "state sponsor of terrorism" for its alleged support of Islamist militants in Somalia, the top U.S. diplomat for Africa said Friday.

The State Department is now compiling data to legally back up such a move, which would impose severe sanctions on the impoverished nation and put it on the same diplomatic blacklist as Cuba, Iran, North Korea, Syria and Sudan, said Jendayi Frazer, the assistant secretary of state for African affairs.

"We are looking into it," she told reporters. "We have to put together the case against them, that information is being collected right now. It will be evaluated through an interagency process and then decisions will be taken."

Frazer, speaking at a briefing called to discuss deteriorating relations between the United States and the increasingly authoritarian country, said Washington stood behind a recent report by U.N. experts that found Eritrea to be the primary source of weapons and cash for Islamist insurgents in Somalia, some of whom have suspected Al Qaeda links.

"We do have intelligence that affirms what's in the monitoring report, but we are still in the process of collecting that data," she said, adding that Eritrea should use the time to avoid being designated a state sponsor of terrorism. "It's an opportunity before they are put on the 'state sponsors' list for them to change their behavior."

The designation, which is rarely used, is nearly a diplomatic death sentence and mandates a wide range of U.S. economic and financial sanctions. The last country added to the list was Sudan in 1993.

Two countries have been removed from the list in recent years: Iraq in 2003, after the U.S.-led ouster of Saddam Hussein, and Libya last year after Tripoli renounced weapons of mass destruction and the use of terrorism.