ADDIS ABABA, June 30 (Reuters) - Ethiopian Prime Minister Abiy Ahmed acknowledged government troops had left Tigray"s regional capital Mekelle after months of fighting, saying it was because the city was no longer the "centre of gravity for conflicts". Another government figure said the troops could return in weeks if needed - the first statements by federal officials since Tigray People"s Liberation Front (TPLF) forces took the city this week in a major turn of events in the conflict. read more But a spokesman for the TPLF called Abiy"s comments a "lie", saying that government troops lost and were forced to leave Mekelle. He also said government-allied Eritrean troops had not withdrawn from the region as an Ethiopian official had claimed. Abiy"s government has been battling the TPLF since late last year, when it accused the then-governing party of Tigray of attacking military bases across the region. The government declared victory over the TPLF after driving its forces from Mekelle at the end of November, but clashes have persisted since in areas outside the regional capital. People in Mekelle, where communications were down on Wednesday, said two days earlier that incoming Tigrayan fighters had been greeted with cheers. There were similar scenes in Shire in northern Tigray on Wednesday, after Eritrean troops had left and Tigrayan forces had entered, residents said. "When we entered Mekelle seven or eight months ago, it was because it was the centre of gravity for conflicts," Abiy told state media on Tuesday in a video posted on his website on Wednesday. "It was the centre of a government. A centre for known and unknown resources. But by the time we exit, there is nothing special about it except that there are some 80,000 people, and those who loot people ... It has lost its centre of gravity in the current context." But TPLF spokesman Getachew Reda said Ethiopian forces were forced to withdraw. "The fact that he"s claiming to have withdrawn from Mekelle is an absolute lie. We bested them in their own game. They lost," Getachew told Reuters on Wednesday. Reuters could not independently verify the conflicting accounts with most communications to the region down. Abiy"s government has come under mounting international pressure to bring an end to the conflict, which has been punctuated by reports of brutal gang-rapes and mass killings of civilians. At least 12 aid workers have been killed. People cheer as they say Eritrean forces have left the northern town of Shire in Ethiopia"s Tigray region, June 29, 2021 in this in this still image taken from video obtained by REUTERS. Ethiopian Prime Minister Abiy Ahmed arrives for the inauguration ceremony of the Meskel square, in Addis Ababa, Ethiopia, June 13, 2021. REUTERS/Tiksa Negeri/File Photo People cheer as they say Eritrean forces have left the northern town of Shire in Ethiopia"s Tigray region, June 29, 2021 in this in this still image taken from video obtained by REUTERS. 1/2 Ethiopian Prime Minister Abiy Ahmed arrives for the inauguration ceremony of the Meskel square, in Addis Ababa, Ethiopia, June 13, 2021. REUTERS/Tiksa Negeri/File Photo Abiy acknowledged in a speech to parliament in March that atrocities including rape have occurred and pledged that any member of the Ethiopian army who committed crimes against civilians would be held accountable. RESPONSE "WILL BE HUGE" At least 350,000 people are facing famine and 5 million others need immediate food aid, the United Nations has said - the worst global food crisis in a decade. "If it is required, we can easily enter Mekelle, and we can enter in less than three weeks," Redwan Hussein, spokesman for the Ethiopian government"s task force for Tigray, told reporters. He also said that forces from neighbouring Eritrea, which residents and aid workers accuse of carrying out abuses against civilians, had withdrawn from the region. But Getachew said that was also incorrect, adding that the Eritreans were gathering in the north and northwestern parts of Tigray in "defence posturing". Eritrea, which sent troops to Tigray in support of Abiy"s government, denied for months that its troops were in Tigray, but later acknowledged their presence while denying they were responsible for abuses. Eritrea"s information minister did not immediately respond to a request for comment on Wednesday. Eritrea fought a brutal 1998-2000 war with Ethiopia, when the TPLF dominated Ethiopia"s central government, and it regards the TPLF as a mortal foe. The Ethiopian army warned Tigray forces against reorganising, saying its response "will be huge". "To those who said they might reorganise, they won"t pass an inch," Lieutenant General Bacha Debele said. "If they try to provoke, our response will be huge and it will be more than the previous one." U.N. Secretary General Antonio Guterres said on Monday he hoped a political solution would be possible. The United States said atrocities should end immediately and warned Ethiopia and Eritrea that Washington would be watching closely. "We will not stand by in the face of the horrors in Tigray," said Robert Godec, acting assistant secretary of state for the State Department"s Bureau of African Affairs.