YANGON, Myanmar (AP) — Security forces in Myanmar have used violence against demonstrators who sought to celebrate last week’s formation of a shadow government to serve as an alternative to the military junta that has held power since a February coup. Myanmar media and posts on social networks say the violence was especially intense in Myingyan, a town in central Myanmar, where they reported at least one person was killed Sunday. Unconfirmed reports on social media said at least one more person was killed there Monday. Marches were held in Mandalay and elsewhere to show support for the “National Unity Government” announced Friday by protest leaders. Security forces reportedly broke up a march at dawn in Mandalay that included Buddhist monks.