The increased number of troops raises fears of a fresh wave of violence in Rakhine. 

Myanmar has sent hundreds of soldiers to northwestern Rakhine state after a recent spate of killings, military sources told Reuters Friday.

Muslim-majority northern Rakhine was plunged into violence last October when Rohingya Muslim militants killed nine border police officers, sparking a security operation beset by allegations of rape, killings and torture by government troops.

Two military sources based in Rakhine told Reuters the army had sent about 500 soldiers to several towns in the state’s northern region near the border with Bangladesh to “help tighten security" after seven Buddhists were found hacked to death in mountains near the town of Maungdaw last week.

“We have to increase security operations because the security situation has worsened — some Muslims and Buddhists have been killed by the insurgents,” Rakhine State police chief Colonel Sein Lwin said to Reuters.

The military representative and a spokesman for Myanmar's de facto leader, Aung San Suu Kyi, were not immediately available for comment.

About 1.1 million Rohingya Muslims live in Rakhine, but are denied citizenship and face restrictions on their movements and access to basic services. The Myanmar government regards the Rohingya as "illegal immigrants" from Bangladesh.

Since the massive counter-offensive last year, about 75,000 people have fled to Bangladesh. United Nations investigators who interviewed some of them said troops likely committed crimes against humanity.

Aung San Suu Kyi’s government rejects the allegations and has refused to cooperate with a U.N. fact-finding mission to look into abuses in Myanmar.

Officials told Reuters the army has tightened security and the police force is on high alert this week. Security forces have also strengthened border guard posts in the region. 

The U.N. has warned aid workers against the "increased likelihood of civil unrest" and the possibility of demonstrations by Buddhists in Rakhine, some of whom say humanitarian agencies give support to Rohingya militants.

The ASEAN Parliamentarians for Human Rights, or APHR, also voiced concern about the increased number of troops in Rakhine. 

“Aung San Suu Kyi should call on all parties, including the Myanmar army, to take steps to de-escalate conflict in northern Rakhine State, rather than exacerbate it,” Eva Kusuma Sundari, a member of its board, said in a statement.