YANGON — Two journalists jailed in Myanmar after they were convicted of breaking the Official Secrets Act walked free from a prison on the outskirts of Yangon on Tuesday after spending more than 500 days behind bars, witnesses said.

The two Reuters reporters, Wa Lone, 33, and Kyaw Soe Oo, 29, had been convicted in September and sentenced to seven years in jail, in a case that raised questions about Myanmar's progress toward democracy and sparked an outcry from diplomats and human rights advocates.

President Win Myint has pardoned thousands of other prisoners in mass amnesties since last month. It is customary in Myanmar for authorities to free prisoners across the country around the time of the traditional New Year, which began on April 17.

Reuters has said the two men did not commit any crime and had called for their release.

Before their arrest in December 2017, Wa Lone and Kyaw Soe Oo had been working on an investigation into the killing of 10 Rohingya Muslim men and boys by security forces and Buddhist civilians in western Myanmar's Rakhine State during an army crackdown that began in August 2017. The operation sent more than 730,000 Rohingya fleeing to Bangladesh, according to U.N. estimates.

The report the two men authored, featuring testimony from perpetrators, witnesses and families of the victims, was awarded the Pulitzer Prize for international reporting in May, adding to a number of accolades received by the pair for their journalism.

A spokesman for the Myanmar government could not immediately be reached for comment.

Myanmar's Supreme Court had rejected the journalists' final appeal in April. They had petitioned the country's top court, citing evidence of a police set-up and lack of proof of a crime, after the Yangon High Court dismissed an earlier appeal in January.

The reporters' wives wrote a letter to the government in April pleading for a pardon, not, they said, because their husbands had done anything wrong, but because it would allow them to be released from prison and reunited with their families.