Republican presidential hopeful Ted Cruz won by wide margins in the Kansas and Maine party caucuses over front-runner Donald Trump Saturday, while Democratic dark horse Bernie Sanders defeated Hillary Rodham Clinton in two Midwestern state races.
But Trump won the southern state of Louisiana with 43 per cent of the vote, and was also leading in Kentucky, early results showed. Clinton also won the Democratic contest in Louisiana.
In Kansas, Cruz won 48 per cent of ballots to Trump's 23 per cent, party officials said. Florida Senator Marco Rubio had 17 per cent and Ohio Governor John Kasich had 11 per cent.
In Maine, Cruz secured 46 per cent to Trump’s 33 per cent. Ohio Governor John Kasich won 12 per cent and Florida Senator Marco Rubio took only 8 per cent, party officials said.
The elections in five states – four for Republicans and three for Democrats - were the first since Super Tuesday, in which a dozen states made their decisions and solidified the front-runner status of both Trump and Clinton in state intra-party contests to determine the nominees of the two main parties for the November election.
The Republican establishment has been struggling to prevent outsider Trump from seizing the conservative party's nomination, and Cruz’s victories Saturday had helped bolster his claims as the conservative alternative.
Poor showings for Rubio, meanwhile, looked to damage his claim as the establishment favourite despite endorsements by many prominent party lawmakers.
Cruz also received a psychological boost from a closely watched straw poll of conservative activists meeting outside Washington who named him their choice for president.
Trump has remained well ahead in polls for the Republican contests, though he has yet to amass enough delegates to put him entirely out of reach of his competitors.
This week both Mitt Romney and John McCain, the 2012 and 2008 Republican presidential nominees respectively, spoke forcefully against Trump being the nominee.
In the Democratic races, Clinton leads voter surveys over Sanders, and also leads in the tally of delegates needed to secure the nomination during a party convention in July.
Sanders won 68 per cent of the vote in Kansas caucuses to Clinton’s 32 per cent. In neighbouring Nebraska, he won 55 per cent to Clinton’s 45 per cent.
However in Louisiana, where there are more minority voters loyal to Clinton, she secured 70 per cent of the vote.