* Government forces moving towards Tigray capital
* Fear of wider conflict spilling beyond Tigray
* Tigray dominated Ethiopia until Abiy's rise in 2018
Rebel forces from Ethiopia's Tigray region fired rockets on Friday at the distant capital of the neighbouring Amhara region, Amhara authorities said, raising worries the conflict could spill into a wider war.
Two weeks into the conflict, the United Nations said it was making plans for as many as 200,000 refugees fleeing into neighbouring Sudan, and made an urgent appeal for $200 million to assist them.
Hundreds, perhaps thousands, of people have been killed and tens of thousands of refugees have fled from fighting in Tigray, raising questions of whether Prime Minister Abiy Ahmed can hold his ethnically diverse nation together.
"The illegal TPLF group have launched a rocket attack around 1:40 a.m. in Bahir Dar," the Amhara government's communications office said, referring to the Tigray People's Liberation Front. The rockets caused no damage, it said.
Bahir Dar, Amhara region's lakeside capital, is located hundreds of miles from the fighting in Tigray. Tigrayan refugees have told Reuters the Amhara militia is fighting on the government side, and the two regions have a border dispute.
A local journalist and another resident in Bahir Dar said they heard two explosions and had been told by people in the area that at least one missile hit near the airport.
Aid agencies fear a humanitarian emergency in Tigray, where hundreds of thousands of people depended on relief aid even before the conflict. Thousands of refugees have fled, some crowding into boats to cross a river to Sudan, overwhelming aid groups positioned on the other side.
"Together with all the agencies we have built a response plan for about 20,000 people and currently we are at about 31,000 so it has already surpassed that figure," U.N. refugee agency's (UNHCR) Axel Bisschop told a briefing in Geneva. "The new planning figure is around 200,000."
UNICEF's Sudan-based representative Abdullah Fadil voiced fears about the impact of the arrivals on Sudan, already hosting 1 million refugees from other African neighbours.
"Our serious concern is if we do not act quickly with the resources needed...this could unravel not only Ethiopia but also Sudan," he told the briefing.
Ethiopia, a federation of 10 ethnic regions, was dominated for decades by Tigrayans in a TPLF-led ruling coalition, until Abiy, who is of Amhara and Oromo descent, took power two years ago. He says he aims to share authority more fairly in the country. The TPLF accuses him of pursuing a vendetta against former officials.
The conflict erupted two weeks ago after what the government called a TPLF attack on army forces stationed in the region.
Tigray forces accused the government of bombing a university in the Tigray capital Mekelle on Thursday. There was no immediate response from the government, although officials have said they are attacking only military targets.
It has been impossible to verify assertions on all sides because telephone lines and internet links to Tigray have been severed since the conflict began.
On Thursday, Ethiopia said it was closing in on Mekelle, which the rebels have said they will defend.
A week ago, Tigray forces fired rockets at two airports in Amhara. They have also fired at rockets into the neighbouring nation of Eritrea, which has a long-running enmity with the TPLF leadership. Eritrea made peace with Ethiopia in 2018, earning Abiy the Nobel Peace Prize.
Reports of ethnically motivated killings have emerged during the conflict. Rights group Amnesty International documented a mass killing of civilians, many of whom appeared to be Amhara, by what it says were Tigrayan forces on Nov. 9-10, which the Tigray authorities denied. Refugees fleeing into Sudan have said they were targeted for being Tigrayan.
Since taking power, Abiy has freed political prisoners and loosened what was once one of the most repressive political and economic systems in Africa. But the new freedoms have been accompanied by bouts of violence as regional bosses vie with each other and the government for power, money and land.
Mountainous Tigray accounts for only about 5% of the population but long dominated the security services. Tigrayans spearheaded a conflict that toppled a Communist regime in 1991.