Turkish President Recep Tayyip Erdogan on Friday accused Myanmar of "genocide" against the Rohingya Muslim minority, who have fled in the tens of thousands across the border into Bangladesh to escape ethnic violence.

"There is a genocide there," Erdogan said in a speech in Istanbul during the Islamic Eid al-Adha feast, which commemorates Abraham's willingness to sacrifice his son.

"Those who close their eyes to this genocide perpetuated under the cover of democracy are its collaborators".

Around 400 people -- most of them Rohingya Muslims -- have died in violence searing through Myanmar's northwestern Rakhine state, the army chief's office said Friday.

Reports of massacres and the systematic torching of villages by security forces -- as well as by militants -- have further amplified tensions, raising fears that communal violence in Rakhine is spinning out of control.

To escape the violence, about 20,000 Rohingya have massed along the Bangladeshi frontier, barred from entering the South Asian country, while scores of desperate people have drowned attempting to cross the Naf, a border river, in makeshift boats.

Erdogan said he would bring up the issue at the next UN General Assembly in New York later this month, adding that he had already talked to UN Secretary-General Antonio Guterres and other Muslim leaders.

According to the state-run Anadolu news agency, Turkish Foreign Minister Mevlut Cavusoglu told Bangladeshi authorities to "open your doors," adding that the country would cover the costs associated with letting in more Rohingya.

Bangladesh already hosts 400,000 Rohingya and does not want more.

"We have called upon the Organization of Islamic Cooperation," Cavusoglu said. "We will organise a summit this year" on the issue. "We have to find a definitive solution to this problem".

The UN Security Council met behind closed doors on Wednesday to discuss the violence, but there was no formal statement on the crisis.

On Friday, Guterres said he was "deeply concerned" by the situation in Myanmar and called for "restraint and calm to avoid a humanitarian catastrophe".

The Rohingya are reviled in Myanmar, where the roughly one million-strong community are accused of being illegal immigrants from Bangladesh.