Kiev. A huge rally has been taking place in the Ukrainian capital to oppose a government decision not to sign a deal on closer EU ties, despite a ban.Casualties were reported after clashes between protesters and police on the fringes of the rally.Police used tear gas and stun grenades to push back protesters near the presidential office.Elsewhere in the city centre, protesters stormed the city council building and took it over.News agencies said about 100,000 people rallied on Kiev’s Independence Square, defying a ban imposed a day earlier.Protesters are demanding the resignation of the government and new elections. President Viktor Yanukovych says Russian pressure was behind his decision not to sign the deal.Demonstrators tried to approach President Yanukovych’s headquarters, commandeering a bulldozer to break through police lines. Police used tear gas and stun grenades to force the crowd back.The Associated Press news agency said that dozens of people with what appeared to be head injuries were taken away by ambulances.A police spokeswoman told AFP news agency that about 100 police were injured in the clashes there.About a kilometre away, at the city council building, protesters broke windows to get inside the building.They chanted "Kiev is ours” and hung a Ukrainian flag in the window. The protests started more than a week ago after President Yanukovych suspended preparations for signing an EU association agreement that would have opened borders to goods and set the stage for an easing of travel restrictions.Mr Yanukovych argued that Ukraine could not afford to sacrifice trade with Russia, which opposed the deal.The Ukrainian president has said he is "deeply outraged” by events at opposition protests in Kiev.