(Reuters) - Three teenagers were arrested on Wednesday and accused of three separate assaults during a demonstration that turned violent outside a rally for presidential candidate Donald Trump last week in San Jose, California, police said.  The three unidentified juveniles, all males, were accused of taking part in a number of skirmishes between Trump supporters and anti-Trump demonstrators last Thursday outside the San Jose Convention Center. Trump held a rally there in the lead-up to Tuesday’s California primary for the Republican party’s presidential nomination. Two of the teenagers, aged 16 and 17, face charges of felony assault with a deadly weapon. The third, also 16, faces a misdemeanor battery charge, the San Jose Police Department said in a statement. One of the teenagers is accused of using a blunt object to strike a victim from behind. The victim suffered visible injuries, according to police.  Four others were arrested during the protests last week. Two 19-year-olds and an 18-year-old face charges of felony assault with a deadly weapon, while another 19-year-old faces a misdemeanor charge of refusal to disperse.  It is unclear whether the seven charged were Trump supporters or among the hundreds of protesters who were seen on news clips waving Mexican flags, chanting anti-Trump slogans, and burning Trump hats and at least one U.S. flag.  Protesters, many angry over Trump’s comments against illegal immigration, have gathered at his rallies for months. Trump, now the Republican Party’s presumptive nominee for the Nov. 8 presidential election, canceled a rally in Chicago in March after clashes broke out between his supporters and protesters. 