SEVERAL hundred protesters threw stones and flares at riot police protecting the US embassy in Belgrade today after Kosovo's declaration of independence, witnesses said.One policeman was injured during scuffles as riot police fought to keep the protesters, mainly hardline football fans, away from the embassy building, the witnesses said. One embassy window was smashed.The protesters marched through the middle of the capital towards the US embassy chanting "Kosovo is Serbia" and anti-American slogans. They waved Serbian flags and vowed to protest "until Kosovo is returned to Serbia".After the scuffles, protesters dispersed in nearby streets, while the police remained around the embassy compound.