A UN human rights expert has expressed grave concerns over a sharp escalation in hostilities in Myanmar’s Kachin State.

The hostilities in the state has reportedly killed at least 10 civilians, left several wounded and forced thousands to flee their homes in the north of the country, according to a press release from the UN.

The Special Rapporteur on the situation of human rights in Myanmar, Yanghee Lee, said she had received reports that the military had carried out aerial bombings, and used heavy weapons and artillery fire against civilian areas near the Chinese border.

“What we are seeing in Kachin State over the past few weeks is wholly unacceptable, and must stop immediately,” Lee said.

“Innocent civilians are being killed and injured, and hundreds of families are now fleeing for their lives,” she said.

She urged all parties to the conflict to abide by their obligations under international humanitarian law, and said it was incumbent upon all forces to observe the principles of distinction, proportionality and precaution, says the press release.

In March, Lee told the Human Rights Council in Geneva that as the world’s attention was focused on the crisis in Rakhine State, violence was escalating in other areas such as Kachin.

According to UN reports, more than 5,000 civilians have been displaced from villages near the border with China in the last three weeks. Children, pregnant women, the elderly and people with disabilities are among those displaced.