The pair now face up to 14 years in prison on charges of possessing classified documents in violation of the colonial-era Official Secrets Act.
Almost 700,000 people have left since the action began last August.
Myanmar's government has denied the allegations.
The Reuters investigation of the Inn Din massacre was what prompted the arrest of two of the news agency's reporters Wa Lone and Kyaw Soe Oo, both Myanmar nationals.
"We are aware of this latest report, the details of which are very alarming". It is looking at the problems in Rakhine state.
The US State Department also said the report showed the need for Myanmar to cooperate in an independent probe.
Mr Johnson is due to tour Rakhine State with representatives from the Burmese military later.
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It contains graphic pictures of the victims before and after the massacre, along with interviews with Buddhists who admitted to setting Rohingya homes on fire and killing Muslims after Rohingya insurgents attacked security posts last August.
There has been no official comment from the government following the publication of the report.
But Myanmar vehemently denies systematic abuses by its security officers, despite a mounting volume of evidence pointing to atrocities.
On Sunday, Mr Johnson will hold talks with Myanmar's de-facto leader Aung San Suu Kyi to discuss the crisis and press for the end to the suffering in Rakhine and the safe and voluntary return of the refugees.
"It is vital that the Rohingya refugees must be allowed to their homes in Rakhine voluntarily, in safety and with dignity, under global oversight, and when the conditions in Burma are right", he said.
"Talking just to some of my fellow foreign ministers from around the world, there is so much confusion still, and I think the role of journalism in setting the record straight is absolutely vital", Johnson said.
The Foreign Secretary's trip to Bangladesh - the first such official visit in a decade - comes after almost 700,000 Rohingya Muslims fled a military crackdown, which began last August.
The Reuters report exposes a long chain of complicity-Myanmar's military, police force and local Buddhist villagers-behind the brutal premeditated murder of 10 Rohingya men who, according to the military, were among a group of "200 terrorists" that attacked security forces but Buddhist villagers told Reuters that no such attack had taken place in Inn Din.