Police from China and Angola have jointly busted a criminal gang that kidnapped Chinese females and forced them into prostitution in Angola, according to China\'s Ministry of Public Security on Tuesday. Police rescued 19 Chinese females during the operation on Oct. 25, when 11 suspects were arrested in Angola and five were caught in China, according to a statement from the ministry. Those female victims and suspects have been transferred back to China, said the statement. In order to boost international cooperation against human trafficking, China had ratified the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, supplementing the United Nations Convention against Transnational Organized Crime, in February 2010. Moreover, Chinese police have entered into cooperation agreements with more than 50 countries, which contain anti-human trafficking terms.