Security officials said the clashes, which erupted as Friday prayers started in the Grand Mosque of Harf Sufiyan, northwest of Sanaa, killed four supporters of slain cleric Hussein Badr Eddin al-Hawthi, and wounded another three.
The official, who spoke on condition of anonymity, said the clashes began when al-Hawthi loyalists attacked police in the mosque, in the province of Amran, about 40km northwest of the capital Sanaa.
And Abdullah Mohsin Dhabaan, a member of the Amran city council, accused the worshippers starting a gun battle with policemen guarding the mosque.
"A group of al-Hawthi's loyalists tried to take over the mosque by shooting the police, which forced the policemen to return fire," Dhabaan said.
The loyalists belong to the Zaidi community, an offshoot of Shia Islam, and are dominant in northwestern Yemen, but form a minority in the mainly Sunni country.
"A group of al-Hawthi's loyalists tried to take over the mosque by shooting the police, which forced the policemen to return fire"
The government had accused al-Hawthi, who was killed in a battle with troops in September 2004, of sedition, forming an illegal armed group and inciting anti-American sentiment.
His followers say authorities wanted to silence his criticism of corruption.
The Zaidi rebels reject as illegitimate the republican government which seized power in a 1962 coup known as the September 26 revolution, overthrowing the Zaidi imamate.
Al-Hawthi expressed strong anti-US views in his mosque sermons and at demonstrations.
The United States provides military training to Yemen and assistance in safeguarding its borders from infiltration by fighters.
The Yemeni government last month released more than 600 Zaidi rebels who had been granted amnesty after being accused of involvement in uprisings against government forces that left hundreds dead over the last two years.