(Clarifies in second paragraph venue "near" where Patten handed back Hong Kong)
HONG KONG, July 1 (Reuters) - Chinese President Xi Jinping swore in Hong Kong's new leader, Carrie Lam, on Saturday as the former British colony marked the 20th anniversary of its handover to Chinese rule.
Security was tight at the harbour-front venue near where two decades earlier, the last colonial governor, Chris Patten, tearfully handed back Hong Kong to Chinese rule at a rain-soaked ceremony.
Britain returned Hong Kong to Chinese rule on July 1, 1997, under a "one country, two systems" formula which guarantees wide-ranging freedoms and judicial independence unseen in mainland China.
Reporting By James Pomfret and Clare Jim, Editing by Anne Marie Roantree