The newspaper said that Phan ThanhHai and Nguyen Van Hai are also suspected of attending a training course in 2008 organised by a Vietnamese overseas political party, Viet Tan.
Correspondents say that Phan Thanh Hai's blog covered various sensitive issues in Vietnam, including a dispute with China over maritime boundaries, controversial bauxite projects, a scandal around a debt-laden state-owned shipbuilder and case studies of famous dissidents.