Vice President Joe Biden rallied with about 600 supporters Monday afternoon at the Port of Burlington and the Democratic vice president took aim at Republican rivals Mitt Romney and Paul Ryan, on topics ranging from taxes to Medicare.

“They didn’t tell you what they’re proposing would actually cause the Medicare Trust Fund — which they want to, they’re so concerned about its solvency — would actually cause it to be insolvent in the year 2016. That’s what would happen under their proposal,” Biden said. “And most of all what they didn’t tell you they’re not actually preserving Medicare at all. They are for a new plan I call VoucherCare.”

Biden also accused Romney of hypocrisy on a key trade issue. Earlier today President Obama announced the U.S. was filing a complaint with the World Trade Organization against China’s subsidies for its auto industry. Romney dismissed it as an “election year stunt” after 43 months of failed action against China. Biden shot back during his remarks in Burlington.

“I seldom ever quote the official Chinese government news agency,” Biden said, getting laughter from the crowd, many of whom are union members. “This — seriously — this was what the Chinese news agency said and I quote — ‘It’s rather ironic that a considerable portion of this China-battering politician’s wealth was actually obtained by doing business with Chinese companies before he entered politics.'”

Biden described Obama’s action on Monday as an effort to get “real, enforceable fair trade” with the Chinese.

“And a level playing field so we can export what the world wants — products that say: ‘Made in America,'” Biden said, as the crowd cheered. “That’s what the world wants — Made in America.”

The crowd started chanting “U-S-A!” in response. 

Biden also took aim at GOP vice presidential nominee Paul Ryan and his fellow Republicans in congress for failing to “make a deal” with the Obama Administration to balance the federal budget.

“Not our plan did they negotiate on, not any of the outside plans,” Biden said. “And Congressman Ryan, he was on that committee called Simpson/Bowles. He quotes about this ‘outside group made up of Democrats and Republicans.’ He voted against the plan to bring the budget back into balance.”

Ryan spoke to a crowd in Des Moines at about the same time Biden spoke in Burlington.

Biden plans to appear in Ottumwa mid-morning Tuesday and in Grinnell early tomorrow the afternoon.

(Reporting by Brian Crozier, KBUR, Burlington)