VICENZA, Italy (Reuters/AFP) - Anti-G8 demonstrators clashed briefly with Italian police on Saturday in the first big protest ahead of next weeks summit of the worlds richest nations. Police in riot gear fired teargas at protesters to prevent them from crossing a bridge and moving closer to a contested US military base in the northeastern city of Vicenza. The demonstrators, some of them wearing motorcycle helmets and with their faces covered, threw bottles and lit fireworks as they were pushed back on the bridge. Several thousand people, most of them marching peacefully, are attending the protest, launched against expansion plans that would make the US base one of the biggest in Europe and more generally against the July 8-10 G8 summit which Italy chairs. We are sick of the powerful governing without consulting the people, said Martina Vultaggio, 29, one of the protest organisers. The leaders of the United States, Japan, Germany, France, Britain, Italy, Canada and Russia, together with those of major emerging economies, will hold talks in the central city of LAquila focusing on the state of the world economy, financial regulation, climate change, trade and development. Anti-capitalist protesters plan a series of demonstrations at different sites against the summit, starting with the one in Vicenza where locals oppose the doubling of the size of the US base, home to 3,000 soldiers of the 173 Airborne Brigade. The Italian government has approved construction of a new 6,000 square metre (64,600 sq ft) base on the site of the old Molin airport on the citys outskirts. The work at the base which has a current troop capacity of 2,750 will enable 1,800 soldiers presently based in Germany to be stationed there. Demonstrators who have regularly cut their way through barbed wire guarding the site cried No arms here and We wont be a rear base for the killing of Afghan kids. Local authorities have backed the extension, with around 1,200 jobs created, while successive governments led by centre-left Romano Prodi and current Prime Minister Silvio Berlusconi have each greenlighted the work. A delegation from the organisers a coalition of Communists, Greens and far-left groups will travel to central LAquila on Sunday to protest at the scene of next weeks G8 summit of world leaders including US President Barack Obama. Despite approval by Rome, Vicenza residents have rejected the base expansion in a referendum. Opponents contend the base poses a threat to ground water, is dangerous for residents and for Vicenzas historic centre, a treasure of Renaissance architecture. The protesters have vowed to march about 3.5 km to the construction site, which has been sealed off by local authorities, and plant flags with anti-base slogans. Around 1,000 police were deployed on Saturday along the route. Prime Minister Silvio Berlusconi is keen to avoid a repeat of the violence that marred a 2001 G8 summit hosted by Italy in Genoa, when a protester was killed and scores of others were beaten up by police. Summit organisers have said the choice of LAquila, which was badly damaged by an earthquake in April that killed nearly 300 people and left 60,000 homeless, should deter violent protests out of respect for the plight of local people. Demonstrators plan to stage a candle-lit night march in the city on July 6 three months after the quake struck.