(CNN) Myanmar's leader Aung San Suu Kyi has denied that ethnic cleansing has taken place against the country's Rohingya Muslim ethnic minority.

Last month, a senior UN official told CNN that potential "crimes against humanity" were unfolding in the region, which has been racked by unrest and largely off limits to journalists and NGO workers since October last year.

UN Special Rapporteur Yanghee Lee said that Suu Kyi should "speak up a little more" to protect the Rohingya, tens of thousands of whom have fled across the border to neighboring Bangladesh in recent months.

The Rohingya are a stateless ethnic minority denied citizenship within Myanmar, where they are regarded as illegal Bengali migrants. There have been frequent outbreaks of violence in Rakhine between the Burmese majority and Rohingya groups.

Responding to Lee's comments, Myanmar government spokeswoman Aye Aye Soe said the administration was "deeply concerned by reports of potential human rights abuses and have already set up an investigation commission."

Unrest

The violence began on October 9, when according to state media, a group of around 300 armed men attacked soldiers and police, sparking an intense crackdown by the Myanmar military.

Who are the Rohingya? The Rohingya are a stateless Muslim minority in Myanmar's Rakhine state thought to number about one million people

Myanmar does not recognize them as citizens or one of the 135 recognized ethnic groups living in the country

Much of this is rooted in their heritage in East Bengal, now called Bangladesh

Though many Rohingya have only known life in Myanmar, they are widely viewed as intruders from across the border

According to Human Rights Watch, laws discriminate against the Rohingya, infringing on their freedom of movement, education, and employment

They are denied land and property rights and ownership, and land on which they live can be taken away at any given time

"We attacked them using our machetes, swords, and knives, and we seized their weapons to use against them," Atah Ullah -- leader of the Harakat al-Yaqeen, or "Faith Movement," which carried out the attack -- told CNN earlier this year.

"We, the vulnerable and persecuted people, have asked the international community for protection against the atrocities by the government of Myanmar, but the international community turned its back on us," he said.

"Finally, we cannot take it anymore."

The Myanmar military has arrested hundreds of people in Rakhine, deployed attack helicopters and allegedly torched villages, causing thousands of refugees to flee the region.

Amnesty International said it has documented "a wide range of human rights violations" since the crackdown began, while Human Rights Watch accused the military of "numerous abuses ... including widespread arson, extrajudicial killings, and systematic rape and other sexual violence."

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Divisions

Suu Kyi was barred from becoming Myanmar's president after the country's transition to limited democracy in 2015, but as state counselor she is the country's de facto leader.

The longtime democracy campaigner and Nobel Peace Prize Laureate told the BBC the situation in Rakhine was more complicated than the international media had made it out to be.

"I think there is a lot of hostility there -- it is Muslims killing Muslims as well, if they think they are cooperating with the authorities," she said.

"It is not just a matter of ethnic cleansing, as you put it -- it is a matter of people on different sides of the divide, and this divide we are trying to close up."

In the run-up to the country's general election in 2015 -- its first democratic vote in decades -- many Rohingya hoped Suu Kyi's National League for Democracy would take up their cause.

She said she'd been pressed to answer questions about her stance on the Rohingya since 2012, when sectarian violence broke out.

"(Reporters) would ask me questions and I would answer them, and people would say I said nothing. Simply because I did not make the statements people wanted, which people wanted me to make, simply to condemn one community or the other," Suu Kyi said.

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Military rule

While Suu Kyi is the most powerful civilian politician in Myanmar, the country's military still possesses a great deal of influence.

Under the constitution -- drafted by the former junta -- the military retains 25% of the seats in parliament, and control of security matters.

rape and torture. Prior to 2015, the military, also known as the Tatmadaw, was accused of a raft of human rights abuses, including use of forced labor and child soldiers

The Tatmadaw is responsible for current security actions in Rakhine, where it has been accused of similar crimes

Suu Kyi denied this week that the military had free rein in the region.

"They are not free to rape, pillage and torture," she said. "They are free to go in and fight. That is in the constitution. Military matters are to be left to the army."

She promised that Rohingya who have fled Myanmar to neighboring countries "will be safe" if they returned.

"We welcome them and we will welcome them back," Suu Kyi said.