Prior to the rally, seven anti-China protestors were arrested in Hanoi after unfurling a banner and shouting "Boycott the Beijing Olympics" through a loudhailer at a market. A Vietnamese American was deported for planning protests against the torch, while a prominent blogger, Điếu Cày (real name Nguyễn Văn Hải), who blogged about protests around the world and who called for demonstrations in Vietnam, was arrested on charges of tax evasion. Outside Vietnam, there were protests by overseas Vietnamese in Paris, San Francisco and Canberra. Lê Minh Phiếu, a torchbearer who is a Vietnamese law student studying in France, wrote a letter to the president of the International Olympic Committee protesting China's "politicisation of the Olympics", citing maps of the torch relay at the official Beijing Olympic website depicting the disputed islands as Chinese territory and posted it on his blog. One day before the relay was to start, the official website appeared to have been updated to remove the disputed islands and dotted lines marking China's maritime claims in the South China Sea.
How many protesters were arrested in Hanoi prior to the rally?
seven