Security forces in Bahrain fired tear gas and arrested protesters on Monday during marches in the market area of capital Manana.
The Interior Ministry said it made a number of arrests.
Among them was rights activist Yousef al-Muhafedha, the acting head of the Bahrain Centre for Human Rights, said his wife Zainab al-Sairafi.
Mr Muhafedha's arrest could stir a further backlash less than a week after a Bahrain court rejected an appeal to overturn the jail sentence of rights centre director Nabeel Rajab.
The court merely cut a year from his three-year sentence on charges of encouraging "illegal gatherings."
The rallies commemorated two protesters killed in 1994.