Bahrain breaks up protests, arrests campaigner: activists DUBAI (Reuters) - Bahraini police fired stun grenades to break up dozens of protesters and arrested around 25 people including a prominent campaigner during anti-government rallies in the capital Manama on Monday, activists said. Sayed Yousif Al-Muhafda, a leading figure at the Bahrain Centre for Human Rights, was detained for joining the opposition marches marking the death of two activists in the 1990s - his second arrest since November, another campaigner told Reuters. The island kingdom, the base of the U.S. Navy's Fifth Fleet, has been in turmoil since pro-democracy protests led by its Shi'ite Muslim majority erupted last year inspired by revolts across the region. Earlier this month, Bahrain's opposition groups welcomed a call by the Crown Prince for dialogue. But meetings have not started and the unrest has continued. Dozens of protesters shouted anti-government slogans in the streets of Manama's old market area then fled into alleyways pursued by police, witnesses said. Up to 100 men and women marched in another street but were also dispersed, they added. Police used at least two stun grenades to break up crowds, but there were no direct clashes with security forces, said people at the scene. The authorities have stepped up efforts to end the unrest in recent months and several activists have been arrested or jailed for organizing or taking part in unlicensed protests. Interior Minister Sheikh Rashed bin Abdullah al-Khalifa announced a temporary ban on rallies and gatherings in November. The move, along with the revocation of the citizenship of 31 Bahrainis accused of fomenting violence, were criticized by Western countries and international rights groups. Muhafda was arrested during the marches, Mohammed al-Maskati, head of the Bahrain Youth Society for Human Rights, told Reuters. Muhafda was detained last month on charges of illegally gathering and taking part in an unauthorized march. Another activist, Zainab al-Khawaja, was jailed for two months in October for tearing up a picture of King Hamad bin Isa. She is also facing charges of inciting hatred against the government. Bahrain's ruling Al-Khalifa family, who are Sunni Muslims, used martial law and help from Gulf neighbors to put down last year's uprising, but unrest has resumed. The opposition says little progress has been made towards its demands for reforms including a parliament with full powers to legislate and form governments. Many Shi'ites complain of political and economic marginalization, a charge the government denies. Reporting by Rania El Gamal; Editing by Andrew Heavens