text: The families of five Chinese feminists detained by police for more than a month facing charges of 'picking quarrels and provoking trouble' have issued a plea to authorities for their release. The female activists were arrested the weekend before International Women's Day, as they were preparing to hand out leaflets about sexual harassment on public transport. The five women - Li Tingting, 25, Wei Tingting, 26, Wang Man, 32, Zheng Churan, 25, and Wu Rongrong, 30 - have been linked to several stunts over the last few years which aim to highlight issues such as domestic violence and the poor provision of women's toilets in China. The Chinese feminist activists (all pictured) have been detained by police for more than a month and face being jailed for up to five years if they are charged with 'picking quarrels and provoking trouble' They now face being jailed for up to five years if they are charged. Prosecutors will announce later today whether the women should be formally arrested, released or have their cases sent back to the police, their lawyers said. The vague charge of 'provoking trouble' has been increasingly used by Chinese police under President Xi Jinping to detain and jail protesters from holding small-scale demonstrations. The activists were described as 'young, kind-hearted, and full of a sense of responsibility to society,' ten of their parents and spouses wrote in a letter to Beijing prosecutors which was posted online on Saturday. 'These five girls, who we care for and love deeply, have not made a mistake, let alone committed a crime,' they said, adding 'they have all striven to uphold our nation's basic policy of gender equality'. Activist Li Tingting, 25, (pictured) poses with letters protesting about the poor provision of female toilets - she and others have since been arrested . 'Supporting gender equality and the interests of women is no crime!' Their detention on March 8 has prompted renewed condemnation of China's tight controls on political activists from human rights groups as well as the US. Police interrogations of the women - several of whom suffer from chronic health problems such as asthma and an unspecified heart condition -have focused on a 2012 stunt named 'Occupy Men's Rooms', one of their lawyers, Liang Xiaojun, told AFP on Sunday. Prosecutors have until Monday to formally approve their arrest or police will be obliged to release the women, he added. The parents said in their letter that the women 'have been detained for over a month and we have not had a decent explanation'. 'Please restore their freedom and dignity as soon as possible!' they added. Meanwhile China has lodged a formal . protest with Washington after U.S. Vice President Joe Biden and . Secretary of State John Kerry called for the release of the 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. 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.' Activtsts Wei Tingting, 26, (left) Wang Man, 32, (right) face charges of 'picking quarrels and provoking trouble' In a statement on Friday, Kerry said the U.S. 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. 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. Zheng Churan, 25, (left) and Wu Rongrong, 30 (right) face being jailed for up to five years if they are charged .
target: Five Chinese feminists have been held by police for more than a month .
  They each face charges of 'picking quarrels and provoking trouble'
  Women activists linked to stunts which aim to highlight issues such as domestic violence and the poor provision of women's toilets in China .
  U.S. Vice President Joe Biden and others have called for their release .