by Reuters,  Phil Stewart, David Lewis

WASHINGTON/NAIROBI (Reuters) – The United States believes Eritrean soldiers have crossed into Ethiopia to help Prime Minister Abiy Ahmed’s government battle a rebellious northern force, despite denials from both nations, a U.S. government source and five regional diplomats said.

Abiy and Eritrea’s President Isaias Afwerki signed a peace pact ending two decades of hostilities in 2018 and now regard the Tigray People’s Liberation Front (TPLF) as a mutual foe.

The U.S. assessment creates a potential policy predicament as Washington views Ethiopia as a major ally in the volatile Horn of Africa but accuses Eritrea of severe rights abuses.

Evidence of Eritrean involvement cited in the U.S. view of the month-long war includes satellite images, intercepted communications and anecdotal reports from Tigray region, five diplomats and a security source all briefed on the U.S. assessment told Reuters.

A U.S. government source confirmed Washington’s growing consensus, which has not previously been reported but matches accounts by some residents, refugees and TPLF leaders.

“There doesn’t appear to be a doubt anymore. It’s being discussed by U.S. officials on calls – that the Eritreans are in Tigray – but they aren’t saying it publicly,” the U.S. government source, who has been privy to the internal calls, told Reuters.

A senior diplomat from another country concurred, saying “thousands” of Eritrean soldiers were believed to be engaged.

The U.S. State Department did not confirm the U.S. conclusions, though a spokesman said it would view any proven Eritrean involvement with great concern and that its embassy in Asmara was urging restraint to officials.

Contacted by Reuters on Saturday, Eritrea’s Foreign Minister Osman Saleh Mohammed said: “We are not involved. It’s propaganda.”

Ethiopia has denied its old foe entered the conflict, though Abiy did say last week some government troops retreated into Eritrea early in the conflict and were given assistance. His spokeswoman told Reuters queries should be directed to Eritrea.

Claims by all sides are near-impossible to verify because most communications to Tigray are down, and the government tightly controls access.