Demonstrators have marched through the Yemeni capital of Sanaa after authorities arrested a female human rights activist early on Sunday.
Police detained Tawakul Karman and her husband close to their home.
Inspired by Tunisia’s Jasmin Revolution, Karman organised two protests last week, calling on Yemenis to oust president Ali Abdullah Saleh.
Protesters accuse Saleh of not doing enough to help the poor.
More than 40 percent of the country’s 23 million people live on less then two dollars (1.40 euros) a day
The AFP news agency reported that between 20 to 30 people were arrested during Sunday’s demonstrations.
Saleh has ruled Yemen for more than three decades and was elected to a new seven-year term in 2006.