ADDIS ABABA, July 22 (Reuters) - Attacks by Tigrayan fighters in Ethiopia"s Afar region have forced over 54,000 people from their homes, an official said on Thursday, and refugees in a camp in southern Tigray described heavy clashes nearby. Tens of thousands of people, meanwhile, rallied in the capital to support Prime Minister Abiy Ahmed, who has faced criticism for his handling of a conflict that threatens to undermine stability in Africa"s second most populous nation. Tigrayan fighters, who want the Ethiopian government to accept their terms before talks on a ceasefire can begin, have taken control of three districts in Afar this week, according to Afar regional spokesperson Ahmed Koloyta. The region is of strategic importance because the main road and railway linking Addis Ababa, landlocked Ethiopia"s capital, with the sea port of Djibouti run through it. Ahmed quoted some of the displaced people as saying Tigrayan fighters had burned houses, looted properties and killed civilians. He provided no evidence and Reuters could not verify his claims independently. Getachew Reda, spokesman for the Tigrayan forces, did not immediately return calls seeking comment on the accusations. Debretsion Gebremichael, leader of the Tigray People"s Liberation Front (TPLF), told Reuters via satellite phone earlier on Thursday that Tigrayan forces were in Afar and they planned to target forces from the neighbouring Amhara region, which has been fighting on behalf of the government. He was not immediately reachable for comment on Ahmed"s claims. Djibouti found the situation in Ethiopia "very worrying", Alexi Mohamed, chief adviser to the president, told Reuters. In southern Tigray, some Eritreans in the Adi Harush refugee camp said there had been heavy fighting nearby on Thursday morning. "We are very afraid. The children are crying and we are praying," one told Reuters by telephone, declining to be named for fear of retaliation. Tens of thousands of refugees from Eritrea, who were in Tigray before the war began, are trapped in two camps on the frontlines - Mai Aini and Adi Harush. The Ethiopian Refugee Agency, ARRA, said in a statement that six refugees had been killed in fighting and two more had died from lack of medical attention. ARRA also said, "In violation of the international humanitarian law, the rebels deployed heavy artilleries in the refugee camps, and there appears (to be) continuous militant activity and sporadic shootings." Reuters could not immediately contact Tigrayan forces for comment. War erupted in November between the TPLF, Tigray"s ruling party, and the military. Three weeks later, the government declared victory when it captured the regional capital Mekelle, but the TPLF kept fighting. At the end of June, the TPLF seized back control of Mekelle and most of Tigray after the government withdrew soldiers. Since then, Ethiopia"s other nine regions announced they were sending forces to support the military against Tigrayan fighters. read more On Thursday, tens of thousands of Ethiopians filled Meskel Square in the capital for a rally to support Abiy, whom many said was being unfairly criticised by foreign nations. "Enemies are scared of our reforms and are working jointly and tirelessly to disturb our sovereignty, to disrupt our national unity and our journey to prosperity," Adanech Abebe, mayor of Addis Ababa, told the crowd. Participants waved signs condemning the TPLF as a "cancer" and showing support for Abiy. Some commended him for filling the $4 billion Grand Ethiopian Renaissance Dam (GERD), which has caused tension with Sudan and Egypt over water rights. Getachew, the TPLF spokesman, told Reuters via satellite phone on Tuesday that Tigrayan forces would do "whatever it takes" to get the government to accept their conditions for ceasefire negotiations. Those include the full withdrawal of government troops and their allies from Tigray"s pre-war borders and the restoration of services such as electricity, telecommunications, transport links and banking. read more On Sunday, gunmen attacked a United Nations" World Food Programme truck convoy, halting the movement of food aid into Tigray. read more