Saturday 6 November 2021: The new rebel alliance includes the TPLF and Oromo Liberation Army (OLA) who both want the government led by Abiy to leave.
The OLA and TPLF have already started fighting alongside each other and this week claimed to have captured the town of Kemise, 325km (200 miles) north of Addis Ababa, on the main road from Tigray to the capital.Speaking in Washington, a Tigrayan representative and former Ethiopian ambassador to the US, Berhane Gebre-Christos, said the aim was to oust Mr Abiy's government by force or negotiations, and establish an interim administration.
"We're trying to bring an end to this terrible situation in Ethiopia, which is created single-handedly by the Abiy government," he said. "Time is running out for him."
Fighting broke out a year ago between government troops and the TPLF, which dominated Ethiopia for decades and now controls Tigray.
The call for military veterans to re-enlist is a sign of how seriously the Ethiopian government is taking the rebel threat.
It comes a day after Prime Minister Abiy gave a defiant message, vowing that his forces would "bury the enemy with our blood and bones" while asking civilians to prepare to defend their neighbourhoods
The government has said it will continue to fight what it calls an existential war. The conflict has entered its second year, with millions displaced and more than 400,000 on the brink of famine.
In a rare statement on the war, the UN Security Council called for an end to fighting, and reiterated their support for the African Union's mediation efforts.
The US embassy has also told all US citizens to leave Ethiopia as soon as possible amid a "very fluid" security situation.