China and Russia have held back a United Nations Security Council statement calling for an end to violence in Ethiopia's Tigray region on Friday evening (local time), diplomats tell international media.

The opposition of the two veto countries puts an end to two days of negotiating a text.

The initiators have given up hope for an explanation, says an anonymous diplomat.

There is no consensus and no explanation is being worked on anymore.

Following on from human rights organization Amnesty International, Human Rights Watch (HRW) accused Eritrean government forces on Friday of having committed a massacre in the city of Aksum.

It is estimated that they killed more than 200 civilians, including children, within 48 hours by the end of November.

HRW is urging the UN to launch an independent investigation into war crimes and crimes against humanity.

In mid-November, regional forces from the Tigray region and militias withdrew from the city of Aksum.

Ethiopian and Eritrean troops then shelled the city.

Eyewitnesses reported that the soldiers randomly fired at civilians, HRW said.

Conflict with local militias

The Ethiopian government launched a military offensive in November against the Tigray People's Liberation Front (TPLF), which was in power in the region of the same name in the north of the country.

There had been tensions between the TPLF and the central government for years.

Meanwhile, other actors are also active, including troops from the former enemy and neighboring Eritrea and militias.

Hundreds of thousands of people in Tigray are reliant on humanitarian aid or have fled.

Mark Lowcock, the deputy secretary-general of the United Nations, said on Thursday that Eritrea must withdraw its troops from the Tigray region.

It was the first time that a UN officer explicitly demanded the departure of Eritrean troops.

Michelle Bachelet, the United Nations High Commissioner for Human Rights, also wants an "objective and independent investigation" into possible war crimes and human rights violations.