ADDIS ABABA: Eritrea slammed the United States on Saturday for slapping new sanctions on the country over the deadly conflict in neighbouring Ethiopia, calling the move "illicit and immoral".

The US measures announced on Friday came in response to Eritrea's decision to send troops into Ethiopia's Tigray region to back Prime Minister Abiy Ahmed in the war against the Tigray People's Liberation Front (TPLF) rebel group.

Eritrean and Ethiopian forces have been accused of carrying out mass rapes and massacres in Tigray and Washington has repeatedly urged Asmara to withdraw its troops. On Saturday Eritrea said the sanctions reflected a "misguided and hostile policy" by the US, and were based on false allegations.

"This unilateral sanction, that shifts blame to and scapegoats Eritrea on the basis of spurious allegations, is in contravention of international law, and constitutes a flagrant breach of... sovereignty," the authoritarian state's ministry of information said in a statement.

"That the primary aim of the illicit and immoral sanctions is to inculcate suffering and starvation on the population so as to induce political unrest and instability is patently clear."

Ethiopia on Saturday declared its support for Eritrea, denouncing the sanctions and urging its former ally Washington to "rescind its decision".

"The real target for sanctions and further tougher actions by the US government and the greater international community should be directed towards the TPLF," Ethiopia's foreign ministry said, stressing that Eritrea was "not an impediment to sustainable peace".