Ethiopia has conducted an air raid on the capital of the northern Tigray region for the fourth day this week, as fighting has intensified between central government and regional forces. Government spokesperson Legesse Tulu said Friday’s air raid targeted a base formerly belonging to the Ethiopian military and now being used by rebel Tigrayan forces as a training site in the regional capital Mekelle. Getachew Reda, spokesperson for the Tigray People’s Liberation Front (TPLF), told the Reuters news agency the attack had hit the compound of Mekelle University. He said he had no information on casualties. Three humanitarian sources in Ethiopia, citing information from Mekelle residents, also told Reuters that the attack had hit Mekelle University. Tigrai TV, which is controlled by the TPLF, reported that the attack hit the main campus of the university and 11 civilians were wounded. Legesse, the government spokesperson, said the university was not hit. Two humanitarian sources also told The Associated Press news agency that the military air raids forced a United Nations humanitarian flight to abandon its landing in Mekelle. Legesse confirmed that authorities were aware of the inbound flight. The development appeared to be a sharp escalation in the intimidation tactics that Ethiopian authorities have used against aid workers amid the intensifying, year-long Tigray war. The aid workers spoke on condition of anonymity because they were not authorised to share the information with the media. Legesse told the AP that authorities were aware the UN flight was in the area but said the UN and military flights had a “different time and direction”. The friction between the government and humanitarian groups is occurring amid the world’s worst hunger crisis in a decade, with close to a half-million people in Tigray said to be facing famine-like conditions. The government since June has imposed what the UN calls a “de facto humanitarian blockade” on the region of some six million people, and the AP has reported that people have begun to starve to death. A military spokesman did not immediately respond to questions about the UN flight, which had planned to land in Mekelle, the main base of humanitarian operations in Tigray. NO WILLINGNESS TO COMPROMISE: Government forces also attacked targets in Mekelle on Monday, Wednesday and Thursday this week. Independent journalist Samuel Getachew told Al Jazeera from Ethiopia’s capital Addis Ababa that “there doesn’t seem to be any willingness to compromise”. “The Ethiopian side keeps saying they are targeting a terrorist organisation that they’ve declared earlier this year. The TPLF is saying the Ethiopian government is creating some kind of genocide. There doesn’t seem to be an end in sight,” Getachew said. “As of Monday, media noted that three people have been killed as a result of the air strikes.” War erupted nearly a year ago between federal troops and the TPLF, which governed Ethiopia for three decades at the helm of a multi-ethnic coalition and now controls the northern region. Thousands of people have been killed and more than two million have been forced to flee. The government air raids this week came amid intensified fighting in Amhara, a neighbouring northern region where the government launched a ground offensive last week to recover territory it lost to the TPLF several months ago. Tigray remains under a communications blackout, making it difficult to verify claims, while areas of fighting in Amhara are largely unreachable as well.