Myanmar is facing a "defining moment" and must stop the violence against its ethnic minority Rohingya population, US Secretary of State Rex Tillerson said on Thursday.
Attacks by Rohingya militants on security posts last month triggered an army operation that has killed more than 400 people, destroyed over 6,800 houses and sent nearly 400,000 Rohingya Muslims fleeing to Bangladesh.
On a visit to London where he met British Prime Minister Theresa May and foreign minister, Boris Johnson, he told a news conference: "I think it is a defining moment in many ways for this new, emerging democracy."
He said he understood that Myanmar's Aung San Suu Kyi, a Nobel prize laureate and de facto head of the government in Myanmar, was in a power-sharing agreement with the military and the "complex situation" in which she found herself.
"I think it is important that the global community speak out in support of what we all know the expectation is for the treatment of people regardless of their ethnicity," he added. "This violence must stop, this persecution must stop."
Meanwhile, security has been further tightened along the borders of northeastern states with Myanmar and Bangladesh to foil any attempt by the Rohingyas fleeing the Rakhine state in Myanmar from entering India, officials said on Friday.
Top Assam Rifles and Border Security Force (BSF) officials in Aizawl and Agartala, however, confirmed that no illegal immigrant has been detected or intercepted in the bordering areas of the northeastern states.
Four states-Arunachal Pradesh (520 km), Manipur (398 km), Nagaland (215 km) and Mizoram (510 km) -- share 1,643-km of mountainous and unfenced border with Myanmar. Counter-insurgency trained Assam Rifles are guarding the India-Myanmar border.
There is a 16-km-wide free zone (8 km on either side of the frontier) along this 1,643-km unfenced border.
"Eight additional companies of Assam Rifles are being relocated at the India-Myanmar border to further strengthen security along the frontiers," Inspector General of Assam Rifles Major General Upendra Dwivedi told the media in Aizawl.
Deputy Inspector General of 23 Sector Assam Rifles Brigadier M.S. Mokha also said in Aizawl that there was no influx of Rohingyas to Mizoram yet.
In view of the apprehension of influx, a high level meeting of various security officials was held at 23 Assam Rifles Headquarters in Aizawl on Thursday.
"Since Mizoram and other northeastern states are sharing a porous border with Myanmar, security forces are keeping round-the-clock land and air surveillance on the influx of illegal Rohingyas along the borders," Dwivedi said.
The meeting was attended by senior officials of Assam Rifles, BSF, Central Reserve Police Force, state police and various intelligence agencies.
Another report adds: Myanmar insisted on Friday it was not barring aid workers from Rakhine State, where a counter-insurgency campaign has sparked an exodus of Muslim Rohingya refugees, but said authorities on the ground might restrict access for security reasons.
Nearly 400,000 Rohingyas have fled to Bangladesh to escape a military offensive that has been described as ethnic cleansing, and raised fears of an unfolding humanitarian crisis.
US Deputy Assistant Secretary of State Patrick Murphy was due in Myanmar this weekend to voice Washington's concerns and press for greater access to the conflict area for humanitarian workers, the State Department said.
"We don't block anyone," Myanmar's government spokesman Zaw Htay told Reuters.
"We don't block any organisations sending aid to those areas but they might have some difficulty travelling where access is restricted by local authorities for security reasons."