NAIROBI (Reuters) - Two U.S. senators have called on their government to consider imposing sanctions on any political or military officials found responsible for human rights violations during a month of conflict in Ethiopia’s northern Tigray region. It was the first such call by U.S. lawmakers since war between Ethiopian federal forces and the Tigray People’s Liberation Front (TPLF) broke out on Nov. 4. The conflict is thought to have killed thousands and displaced more than 950,000 people, according to United Nations estimates, about 50,000 of them into Sudan. Concern has mounted over reports of civilians targeted by both sides. That poses a policy dilemma for the United States, which considers Ethiopia an important ally in a volatile region, especially against al Qaeda-linked Islamist militants al Shabaab in neighbouring Somalia. The proposed resolution was introduced on Wednesday by Senator Ben Cardin, a Democrat, and Senator Jim Risch, a Republican. “The ongoing fighting in Tigray has already cost thousands of lives and created a humanitarian crisis of disastrous proportions, threatening the long-term stability not only of Ethiopia, but the entire region,” Cardin said in a statement. U.N. High Commissioner for Human Rights Michelle Bachelet on Wednesday called events in Tigray “worrying and volatile” and and called for independent monitoring of the human rights situation. Ethiopian Prime Minister Abiy Ahmed’s spokeswoman Billene Seyoum responded on Thursday that there was “nothing volatile about Tigray or Ethiopia”. “The federal government is well equipped and able to restore order,” she said. A spokesman said the government will investigate any reports of atrocities or mass killings, but rejected independent investigations as long as Ethiopia is able to do them itself. The Ethiopian army has captured Tigray’s regional capital Mekelle and declared victory, but TPLF leaders say they are fighting back from mountains around the city. Accounts from all sides are difficult to verify because most phone and internet connections to the region have been down throughout the conflict. Foreign journalists cannot leave the capital, Addis Ababa, without permits. When Abiy took power in 2018 after nearly three decades of heavy-handed rule by a TPLF-led coalition, he freed journalists and activists, and unbanned political parties. He also ended two decades of conflict with the neighbouring nation of Eritrea, for which he won the Nobel Peace Prize last year. But the TPLF was angered when Abiy’s government arrested dozens of senior Tigrayan officials on charges of corruption and rights abuses in 2018. The wife and son of Ethiopia’s ex-foreign minister Seyoum Mesfin, a TPLF stalwart, appeared in court on Thursday, charged with distributing money to youth to incite violence in Addis Ababa, state media reported. REPORTS OF ATROCITIES Civilians fleeing fighting in Tigray last month told Reuters that they witnessed bombing by government warplanes, shooting on the streets, and people being hacked to death with machetes. Ethiopia’s state-appointed human rights commission’s initial report found that an estimated 600 civilians had been stabbed or hacked to death in the town of Mai Kadra in Tigray less than a week after the war began. On Thursday, Frehiwot Tamiru, head of the state-run monopoloy Ethio-Telecom, blamed Tigray’s communications outages on sabotage by TPLF forces. Aid agencies meanwhile complain of blocked access and bureaucratic delays to aid deliveries to Tigray, home to more than 5 million people. Around 600,000 relied on food handouts even before the conflict. Four, possibly five aid workers have been reported killed in the conflict so far. On Thursday, the International Rescue Committee confirmed that among the dead was one of its staff members, killed in unclear circumstances in in Hitsats refugee camp, which housed Eritrean refugees, near the central town of Shire. A U.N. team that attempted to approach the refugee camps earlier this week was shot at and the areas remain off limits to aid agencies. The government says it is delivering aid to areas it controls. On Thursday the Ministry of Peace announced that 1.2 million tonnes of food aid, including wheat, had arrived in Mekelle.