More than 1,000 people have joined a second day of planned rallies in the US city of St Louis to protest against police shootings.

Police said several arrests were made for "illegal behaviour" and that rocks had been thrown by protesters.

The four-day event, named Ferguson October, began on Friday with a march outside the local prosecutor's office.

Weeks of protests were sparked by the killing of unarmed black teenager Michael Brown in nearby Ferguson.

Tensions in St Louis are high after another black teenager, Vonderrit D Myers, was shot dead by a police officer on Wednesday.

Officers in riot gear used pepper spray to try to dispel angry demonstrators after Myers' shooting last week.

Police said 18-year-old Myers shot at an officer, but the victim's parents say he was unarmed and racially profiled.

'Civil disobedience'

Saturday's demonstrations began with a peaceful march through the centre of St Louis to the Keiner Plaza park. The crowd was larger than the day before, according to the Associated Press.

"This isn't going to stop until there is change with police and black youth," Tory Russell, one of the organisers, told the news agency.

In the early hours of Sunday, St Louis chief of police Sam Dotson tweeted that arrests had been made and said protestors had thrown rocks at police.

The first Ferguson October protest on Friday saw hundreds of demonstrators line up against police in riot gear outside the office of the St Louis prosecutor Robert McCulloch.

Demonstrators chanted slogans calling for Mr McCulloch to charge Darren Wilson, the officer who shot Mr Brown in August.

Protest organisers said the weekend of events was intended "to build momentum for a nationwide movement against police violence".

"We are here to bring peace, to bring restoration, to lift our banners in the name of those who've been sacrificed," said another protest organiser, Montague Simmons.

The events will include street protests as well as a music event and a day of "civil disobedience".

Organisers have urged people from across the US to attend.

A US justice department investigation into the shooting of Michael Brown in August is continuing.
(BBC)