BEIJING — The Chinese authorities have released a prominent #MeToo activist and journalist whose detention nearly three months ago prompted an outcry from human rights groups, her friends said on Friday.

The activist, Huang Xueqin, 32, was detained by the police in October in the southern city of Guangzhou on charges of “picking quarrels and provoking trouble,” a vague accusation that the government often uses to silence activists.

Ms. Huang gained prominence as a #MeToo activist who confronted China’s patriarchal culture, helping dozens of women report cases of sexual harassment. More recently, she had drawn attention for traveling to Hong Kong and writing essays about the antigovernment protests there.

In a message to her friends on Friday, Ms. Huang said she was grateful for their support.

“This is Xueqin, and I’m back,” she wrote, according to a friend who received the message and asked not to be identified. “One second of darkness doesn’t make people blind.”