(Updates with foreign ministry statement in paragraphs 5-6) By Yimou Lee and Christopher Bing TAIPEI/WASHINGTON, Aug 2 (Reuters) – Digital attacks against Taiwanese government websites ahead of U.S. House of Representatives Speaker Nancy Pelosi's arrival in Tapei on Tuesday were likely launched by Chinese activist hackers rather than the Chinese government, a cybersecurity research organisation said. The website of Taiwan's presidential office was targeted by a distributed denial of service (DDoS) attack on Tuesday and was at one point malfunctioning, the office said in a statement. Access to the website was restored within about 20 minutes of the attack, the…