Washington - Republican presidential candidate Donald Trump on Saturday slammed 2008 Republican presidential nominee John McCain on his status as a "war hero", and is being slammed by his fellow Republican candidates as a consequence."He's not a war hero. He's a war hero because he was captured," Trump said of McCain, according to the Washington Post. "I like people that weren't captured."McCain spent six years as a prisoner of war in North Vietnam after his fighter plane was shot down while on a combat mission.Billionaire Trump made his remarks at a gathering of social conservative activists in Ames, Iowa, where many presidential hopefuls are campaigning ahead of that state's primary election.Republican leaders and other presidential candidates were quick to condemn Trump for his remarks.Texas governor and Republican presidential candidate Rick Perry tweeted "as a fellow veteran I respect @SenJohnMcCain because he volunteered to serve his country. I cannot say the same about Mr @realDonaldTrump."Perry also tweeted that Trump's comments make him "unfit" to be president.Wisconsin Governor Scott Walker, himself a Republican presidential contender, also took to Twitter to denounce Trump: "@SenJohnMcCain is an American hero, period. I'll denounce any attack against his service and anyone else who wears the uniform."Controversial statements have been a hallmark of Trump's campaign to date, with his most incendiary being about undocumented Mexican immigrants living in the US.