|The protesters chanted slogans against President Saleh, including 'Down with the president's thugs' [Reuters]
Thousands of people have protested in Yemen for a fifth consecutive day to demand political reforms and the overthrow of the country's president.
They were met by pro-government supporters, who waded into Tuesday's protest in Sanaa with batons, sparking violent clashes in which three people were hurt, the AFP news agency said.
The loyalists were joined by plainclothes police wielding electric tasers, who sent the crowd of around 3,000 protesters, mostly students and rights activists, fleeing, witnesses said.
The demonstrators chanted slogans against Ali Abdullah Saleh, the Yemeni president, such as "Down with the president's thugs".
"What we are seeing is thousands of pro-government protesters, armed with batons, attacking the pro-democracy protesters and dispersing the crowd using violence," Al Jazeera's Hashem Ahelbarra reported from the scene of the protests.
A heavy police force and about 2,000 pro-government supporters had positioned themselves at the city centre.
Our correspondent said that it was very difficult for international news organisations to operate.
"The situation is very tense - the government has been describing the pro-democracy protesters as traitors and accusing them of pushing foreign agendas," he said.
"But the [anger] of the pro-democracy protesters is on the rise and they are saying that they will continue their fight to bring down this regime and to bring about a change."
Protesters have been using social media networks, such as Facebook and Twitter, in an attempt to mobilise people throughout Yemen, an impoverished country at the south of the Arabian peninsula.
But security forces have blocked access to public squares, several coincidentally named "Tahrir Square" - both in Sanaa, and around the country.
The move was an apparent attempt to prevent the world media from linking the protests with those that took place in the Egyptian capital, Cairo, Al Jazeera's Ahelbarra said.
Several checkpoints have appeared on the streets leading to Sanaa's presidential palace, and many have been blocked with razor wire.
The protests have been continuing despite Saleh's pledge not to seek another term in 2013.
On Monday, a 3,000-strong throng of demonstrators, clad in black robes, clashed with police and pro-government supporters in Sanaa.
Military ties between the US and Saleh's administration have grown stronger in recent months, as the country struggles with the increasing militancy of a secessionist movement in the south, as well as unrest provoked by rising food prices, unemployment reaching 40 per cent - and demands for human rights to be recognised.
The US is shortly to embark on a $75m project to train Yemen's counterterrorism unit, US officials say.
Saleh became leader of North Yemen in 1978 and has ruled the Republic of Yemen since the north and south merged in 1990.