Rohingya women cry after being restricted by members of Border Guards Bangladesh (BGB) to further enter into Bangladesh, in Cox’s Bazar, Bangladesh August 28, 2017.

:: Rohingya Muslims fleeing to Bangladesh from escalating violence in Myanmar face the growing danger of sickness and attempts by the Bangladesh authorities to send them home, despite a United Nations plea that they be allowed to seek shelter.

A series of coordinated attacks by Rohingya insurgents on security forces in the north of Myanmar’s Rakhine state on Friday has triggered a fresh exodus to Bangladesh of Muslim villagers trying to escape the violence.

At least 109 people have been killed in the clashes in Myanmar, according to the government, most of them militants but including members of the security forces and civilians.

Bangladesh border guards told Reuters they had sent about 550 Rohingya back across the Naf river that separates the two countries since Monday, despite an appeal by UN Secretary-General Antonio Guterres for Dhaka to allow Rohingya to seek safety.

Border patrols were also trying to block people from crossing the frontier.

The treatment of about 1.1 million Muslim Rohingya in Myanmar has become the biggest challenge for national leader Aung San Suu Kyi, who has been accused by Western critics of not speaking out on behalf of a minority who have long complained of persecution.

The Rohingya are denied citizenship in Myanmar and classifiedas illegal immigrants, despite claiming roots there that go back centuries.

The violence marks a dramatic escalation of a conflict that has simmered since October, when a similar, but much smaller, series of Rohingya attacks on security posts prompted a fierce military response dogged by allegations of human rights abuses.

The top UN human rights official, Zeid Ra’ad al-Hussein, called on Myanmar on Tuesday to ensure its security forces refrained from using disproportionate force, adding that the political leadership had a duty to protect all civilians “without discrimination”.

“This turn of events is deplorable. It was predicted and could have been prevented,” he said.

Myanmar’s National Security Adviser Thaung Tun said at a news conference that Myanmar had come under attack and had the full right to defend itself. He added that “security personnel have been instructed to make sure that innocent civilians are not harmed”.