The latest explosions came just hours after Ethiopian Prime Minister Abiy Ahmed declared victory in his government’s fighting against forces of the Tigray People’s Liberation Front, which runs the northern Tigray region bordering Eritrea.
Rockets launched from Ethiopia's northern Tigray region have again targeted the capital of Eritrea while the US embassy in Asmara has reported there have been "six explosions" in the city.
The "explosions" – which the embassy said occurred "at about 10:13 pm" (19:13 GMT) on Saturday night – came hours after Ethiopian Prime Minister Abiy Ahmed declared victory in his military campaign against Tigray's ruling party, the Tigray People's Liberation Front (TPLF).
The TPLF justified that attack by accusing Ethiopia of enlisting Eritrean military support for its campaign in Tigray, something Ethiopia denies.
Two Addis Ababa-based diplomats said that multiple rockets fired on Saturday night appeared to have targeted Asmara's airport and military installations, though as with previous attacks it was unclear where they landed and what damage they might have caused.
'Complete and cease' Tigray offensive
Ethiopian Prime Minister Abiy Ahmed earlier said that military operations in the region have been completed, shortly after he announced federal troops had seized full control of the regional capital of Tigray.
"I am pleased to share that we have completed and ceased the military operations in the Tigray region," Abiy tweeted on Saturday.
"We've been able to enter Mekelle city without innocent civilians being targets."
Ethiopia's military said it gained full control of Mekelle after Tigray TV reported that the city of a half-million people was being "heavily bombarded" in the final push to arrest the region's leaders.
The army chief of staff, General Birhanu Jula, made the comment while speaking on an Ethiopian state broadcast.
Neither mentioned the arrest of any of the leaders of the Tigray People's Liberation Front (TPLF), which runs the region.
"Our focus now will be on rebuilding the region and providing humanitarian assistance while Federal Police apprehend the TPLF clique," PM Abiy said.
The leader of the rebellious Tigrayan forces told Reuters news agency in a text message that they will continue fighting the Ethiopian government, hours after the government's declaration.
"Their brutality can only add (to) our resolve to fight these invaders to the last," said Debretsion Gebremichael in a message. Asked by Reuters in a text message if that meant his forces will continue fighting, he replied: “Certainly. This is about defending our right to self determination.”
Earlier, Gebremichael told Reuters in a text message that Mekelle was under "heavy bombardment."
Ethiopia's military "has started hitting with heavy weaponry and artillery the centre of Mekelle", the local government said in a statement carried by Tigrayan media – a claim confirmed by two humanitarian officials with staff in the city.
"The Tigray regional state calls upon all who have a clear conscience, including the international community, to condemn the artillery and warplane attacks and massacres being committed," the statement said.
The Ethiopian army said on Saturday it would take control of Mekelle "within a few days", according to a report from state-affiliated Fana Broadcasting Corporate.
Fighting resumes after ultimatum
Billene Seyoum, a spokeswoman for Prime Minister Abiy Ahmed's office, said that Ethiopian forces would not "bombard" civilian areas, adding "the safety of Ethiopians in Mekelle and Tigray region continues as a priority for the federal government."
The government gave the TPLF an ultimatum last Sunday to lay down arms or face an assault on Mekelle, a city of 500,000 people, raising fears among aid groups of extensive civilian casualties. The ultimatum expired on Wednesday.
Abiy told African peace envoys on Friday that his government will protect civilians in Tigray. But Abiy has said he regards the conflict as an internal matter and his government has so far rebuffed attempts at mediation.
"The United States is gravely concerned about the worsening situation in the Tigray region," the US ambassador to the UN, Kelly Craft, tweeted after the reported bombardment began.
She called for dialogue, the protection of civilians, and access to aid.
"I invite everyone to pray for Ethiopia where armed clashes have intensified and are causing a serious humanitarian situation," Pope Francis tweeted.
READ MORE: Ethiopian forces surround Tigray's capital Mekelle as ultimatum expires
Raids in Eritrean refugee camps
TPLF leader Debretsion also accused the military of the neighbouring nation of Eritrea of raiding refugee camps in Tigray to capture refugees who had fled Eritrea.
Reuters was not immediately able to get comments from the Eritrean government, which has not responded to calls from Reuters for more than two weeks.
Claims from all sides are difficult to verify since phone and internet links to the region have been down and access tightly controlled since fighting began three weeks ago between forces of the government and the TPLF.
The TPLF and Eritrea are archenemies: the TPLF was in charge in Addis Ababa when Ethiopia and Eritrea fought a war from 1998-2000.
But Eritrea and Abiy have warm relations. The Ethiopian government has denied TPLF accusations that Eritrean troops are operating on Ethiopian soil.
Eritrea is one of the world's most repressive nations. It has never had elections and no independent media has operated there for two decades. Upon turning 18, Eritrean men and women must enter compulsory service to the state for an indefinite amount of time. Around 10 percent of the population has fled.
On Friday evening in Eritrea, "a loud noise, possibly an explosion" was heard in the capital Asmara, the US Embassy there said in a statement early on Saturday.
TPLF rockets hit Eritrea on November 14.
READ MORE: Ethiopia's new stance on Eritrean asylum-seekers criticised
Letter to envoys threatens expulsion
On Friday, a letter was sent to embassies in Addis Ababa warning defence attaches that they risked expulsion if they were in contact with unnamed enemies of Ethiopia.
"Some military attaches are working with those who endangered the security of the country, identified in blacklist and sought by attorney of the court," said the letter.
The letter was stamped by Brigadier-General Boultie Tadesse of the Defence Foreign Relations Directorate, on the copy of shown to Reuters.
"We will expel those who do not refrain from their actions who are in contact with those extremist group."
A military spokesman and the head of the government's Tigray task force did not respond to requests for comment.
Billene, the prime minister's spokeswoman, said she could not address questions about the letter, including whether it was referring to the TPLF, without seeing the original document.
READ MORE: UN urges civilian protection as Ethiopia warns of ‘no mercy’ in assault
UN – Sudan needs $150M to help refugees
The Ethiopian military has been fighting forces in the northern region of Tigray, which borders the nations of Eritrea and Sudan, since November 4.
Abiy accuses Tigrayan leaders of starting the war by attacking federal troops at a base in Tigray. The TPLF says the attack was a pre-emptive strike.
Thousands of people are believed to have died and there has been widespread destruction from aerial bombardment and ground fighting since the war began. Around 43,000 refugees have fled to Sudan.
"Sudan needs $150 million for six months to provide these refugees water, shelter, and health services," said UN High Commissioner for Refugees Filippo Grandi on Saturday at Um Raquba camp, some 80 kilometres from the border.
Grandi called on "donors to provide Sudan with these resources as soon as they can".
Tigrayans, who make up about six percent of Ethiopia's 115 million population, dominated the government until Abiy took power two years ago.
Abiy pledged to unite Ethiopians and introduce freedoms after years of state repression that filled jails with tens of thousands of political prisoners. His government also put senior Tigrayan officials on trial for crimes such as corruption, torture, and murder.
The Tigrayan region saw those trials as discrimination.
Abiy's reforms created more political space but also lifted the lid on long-repressed tensions over land and resources.
READ MORE: Ethiopia's Abiy rejects talks with Tigray leaders ahead of planned assault