US Republican presidential candidate Ted Cruz has won a nominating contest in Kansas and was leading in Maine, denting frontrunner Donald Trump’s momentum and bolstering Cruz’s case that he is the best alternative for those bent on stopping Trump.

Kansas was one of five states holding nominating contests on Saturday, and Trump and Democrat Hillary Clinton were looking to strengthen their leads in the battle to pick nominees for the November 8 presidential election to succeed President Barack Obama.

• Trump, Clinton are still a long way from winning
• Trump refuses to reject KKK-linked endorsement
• Hilary Clinton wins South Carolina

Republicans in Louisiana, Kentucky and Maine also were voting on Saturday.

Cruz led in very early results in Maine; results in the other states were expected later in the night.

Trump has been on the end of blistering attacks. Getty

Cruz, a US senator from Texas who has promoted himself to voters as a true conservative, in contrast to Trump, also won a non-binding “straw poll” of activists at the Conservative Political Action Conference near Washington, DC.

“What we saw in Kansas is a manifestation of a real shift in momentum,” Cruz told reporters in Idaho.

Trump has a substantial lead in the delegates needed to secure the nomination at the Republican National Convention, but has come under a barrage of blistering attacks from his party’s establishment.

The four Republican contests on Saturday together account for just 155 delegates.

Since winning seven of 11 contests on Super Tuesday, Trump has come under withering fire from a Republican establishment worried he will lead the party to a resounding defeat in November’s election.

The anti-Trump forces have a short window to stop the caustic businessman, who has accumulated 319 of the 1,237 delegates needed to win the nomination at July’s Republican national convention, outpacing Cruz, who has 226 delegates.

On March 15, the delegate-rich states of Florida, Illinois, Ohio, Missouri and North Carolina will vote.

Clinton: big lead in Louisiana.

Both Florida and Ohio use the winner-take-all method to allocate Republican delegates, making the stakes in those two states particularly high.

If Trump takes Florida and Ohio he would be nearly impossible to stop. There are a total of 358 delegates at stake in the five states voting March 15, including 99 in Florida and 66 in Ohio.

On the Democratic side, voters in Louisiana, Kansas and Nebraska were weighing in on Saturday on the race between Clinton, the former secretary of state, and Bernie Sanders, a US senator from Vermont.

Polls show Clinton with a big lead in Louisiana, which has a large bloc of the African-American voters who helped her roll up victories across the South on Super Tuesday. But the caucuses in less diverse Kansas and Nebraska could be more suited to Sanders. The three states have a total of 109 delegates at stake.