NAPYITAW — Myanmar's powerful ruling party chief Shwe Mann has been ousted from his post, party members said on Thursday, apparently after losing a power struggle with President Thein Sein three months before a general election. The feud between the two old rivals became public in a dramatic way late on Wednesday evening, when security forces surrounded the vast headquarters of the ruling Union Solidarity and Development Party (USDP) in the capital, Naypyitaw. The United States expressed concern about the apparent use of security forces to help resolve the dispute. Shwe Mann's ouster from the party follows rare discord within the establishment over the role of the military, which handed power to a semi-civilian government in 2011 but retains an effective veto over changes to the political system. Shwe Mann had built ties with Nobel laureate and opposition leader Aung San Suu Kyi, who has called repeatedly for the military to withdraw from politics. — Reuters