BEIJING — China has lodged a formal protest with Washington after US Vice President Joe Biden and Secretary of State John Kerry called for the release of five detained women activists, the foreign ministry said on Monday. The tussle over the activists could further strain ties between China and the United States, which frequently grapple over everything the value of the yuan currency to China's growing military assertiveness. The women, Li Tingting, 25, Wei Tingting, 26, Wang Man, 32, Zheng Churan, 25, and Wu Rongrong, 30 were taken into custody on the weekend of March 8, International Women's Day, after they had planned to demonstrate against sexual harassment on public transport, such as buses and trains. Biden tweeted on Saturday that China should release them, saying, “We urge Chinese leaders to show respect for women's rights,” and adding, “Rights of women and girls should never be suppressed.” In a statement on Friday, Kerry said the US government backed the efforts of the activists, saying, “We believe that Chinese authorities should also support them, not silence them.” China has lodged “representations” with the United States over the comments, Foreign Ministry spokesman Hong Lei said. “We urge the United States to respect China's judicial sovereignty and not use any pretext to interfere in China's internal affairs,” he told a daily news briefing. “China is a country of rule of law,” Hong added. “China's legal authorities will handle this case in accordance with the law.” Hillary Clinton, the Democrats' 2016 presidential front-runner, annoyed Beijing last week with similar calls to free the women. Britain and the European Union have also expressed concern about the case. Police in Beijing have asked prosecutors to charge the activists with “gathering a crowd to disturb public order,” their lawyers said. Police did not respond to a request for comment. Prosecutors were expected to announce later on Monday whether the women should be formally arrested, released or have their cases sent back to the police, according to the lawyers. Their detentions have galvanized the rights community, which is reeling from a sustained clampdown on dissent. President Xi Jinping's administration has detained hundreds of activists in the past two years, in what some rights groups say is the worst suppression of human rights in two decades. Activists say the women's cases have become a measure of Beijing's resolve in crushing all forms of civil society, even if their actions are overtly political. The detained women participated in a 2012 campaign to press for more public toilets for women and a 2013-14 campaign against domestic violence. — Reuters