An agitated Rick Santorum on Sunday called Mitt Romney 'the worst Republican in the country to put up against Barack Obama' even as it appears the former Massachusetts governor is on pace to clinch the party's nomination in June.

Santorum later lashed out at reporters, using profanity as he accused them of twisting his speech.

Santorum told voters that Romney is 'uniquely disqualified' to be the GOP's presidential pick and urged his supporters to stand with him even as he faces an increasingly improbable pathway to the nomination.