ST PAUL, Minnesota (AFP) - Thousands of people including disgruntled Republicans bearing banners and peace flags, gathered and shouted in one voice to end the war in Iraq. The protestors marched through the streets of St Paul on Monday urging Republicans gathered for the party convention to bring US troops home. Snipers looked on from nearby buildings and a helicopter hovered overhead, at times drowning out the shouts from the parade. Trouble flared when one group split away from the beginning of the march and smashed a store window, triggering a clash with police, who fired pepper spray on the crowd, including at an AFP photographer. The police told AFP they had arrested about 100 people. Security has been tight in St Paul, in a bid to avoid a repeat of the chaotic scenes seen at the 2004 Republican convention in New York when more than 1,800 people were arrested. But the atmosphere in St Paul, Minnesota, was mostly festive with demonstrators keen to press their message, even though they went unheard by delegates inside the centre as they herded through a fenced-in walkway. "I'm here for all the Iraqi women who can't be here," said 72-year-old Mim Olsen, from Texas. "It can be very lonely out there, if you are grieving. So this kind of gathering is important for each other, to say to everyone that we are all members of the human family", she said. As the march got underway, some demonstrators tried to taunt the riot police stationed at key intersections, visors covering their faces, long wooden truncheons braced at the ready. The mostly-women marshals from the organisers of the "March on the RNC" rally anxiously shepherded people past potential flashpoints on the short parade from the capitol building. Iraq veterans against the war fell in step with mothers pushing prams and rowdy students shouted anti-government slogans. Some estimated there were about 10,000 people in the crowd, far fewer than the 50,000 the organisers had hoped for. "We joined up with an altruistic vision of promoting freedom and justice around the world," said Vince Emanuel, a Marine lance corporal who did a tour of duty in Iraq from August 2004 to April 2005. "Except we saw the killing of innocent people and the destruction of property, for a lot of us it was very disenfranchising", he added. The veterans group tried to hand a message to the campaign of Republican White House hopeful John McCain calling for a withdrawal from Iraq, reparations for the Iraqi people, and full medical benefits for veterans. No one from McCain's campaign received them, Emanuel said. Earlier, demonstrators had gathered on the steps of the capitol building, listening to a giant rally. Families lounged in the hot sun. "This is a once in a lifetime chance," said Allysen Hoberg, 32, from Minneapolis. Randy Harmen, from Colorado, was signing a giant poster bearing the preamble of the US constitution. Members of the group "Grandmothers for Peace" rubbed shoulders with "Psychologists for Peace". There was even a group called "Loons for Peace," referring to Minnesota's state bird. "Well I just think those lunatics in Washington are giving our state bird a bad name," said St Paul, a resident of Barbara Peterson as she waved her home made bird banner.