They were charged with several offences, including incitement to violence.

Kisumu is a centre of opposition to the proposals, which critics say will leave too much power with the president.

Internal Security Minister John Michuki said on Sunday the government would deal ruthlessly with people causing chaos.

Minister accused

"(They) should know that there is an elected government firmly in place whose cardinal duty is to protect its people," he said during a pro-constitution rally in the capital, Nairobi.

MP Maina Kamanda said Roads Minister Raila Odinga should be arrested for questioning over the Kisumu violence, Kenya's Daily Nation newspaper reports.

Mr Odinga is part of the ruling coalition but has joined with the main opposition party, Kanu, to campaign against the proposals, using the symbol of an orange.

President Mwai Kibaki's government is leading the "Yes" campaign under the symbol of a banana.

If the new constitution is approved on 21 November, it would be the first major overhaul of Kenya's constitution since independence from Britain in 1963.

Critics of the draft say it fails to establish a strong prime minister's post, which they say would prevent the president abusing his powers.

Instead, the premier is appointed and can be dismissed by the president.