Police in Myanmar on Saturday arrested a photojournalist who posted a satirical message on Facebook that mocked a historic battle and the country’s leader. Police confirmed they detained Aung Nay Myo, a feelancer, on a charge of violating the 1950 Emergency Provision Act. If found guilty, he could face a maximum seven years in prison. His post satirized the 1971 battle between government troops and communist fighters and wrote that it was directed by President Thein Sein. The government often uses the draconian law to persecute dissidents and political activists. At least nine journalists and several publishers and media owners are serving prison sentences from two to seven years and nearly a dozen others are facing charges, undermining modest advances in media freedoms in Myanmar following a half-century military rule.