US presidential hopefuls Donald Trump and Hillary Clinton have maintained their status as front-runners in the latest round of voting for their party's nomination, reports the BBC.
Despite defeats to Ted Cruz in Kansas and Maine, Republican Mr Trump won in Louisiana and Kentucky.
Other Republican contenders Marco Rubio and John Kasich made little progress.
Mrs Clinton lost to Bernie Sanders in the Democratic races in Kansas and Nebraska, but won in Louisiana.
Mr Cruz now appears to be the only candidate who can stop Mr Trump, analysts say, after a week in which the Republican establishment did everything it could to attack Mr Trump.
Observers also point out that Mr Cruz and Mr Sanders both won in caucuses but appear to have lost in the Louisiana primary elections, involving far more voters.
The Democratic race in Louisiana-- comfortably won by Mrs Clinton-- also appears to have exposed Mr Sanders' lack of support among African-American voters.
"God bless Kansas," Mr Cruz said during a rally in Idaho, which votes in three days. "The scream you hear, the howl that comes from Washington DC, is utter terror at what we the people are doing together."
Earlier, at a rally in Florida, Mr Trump said: "Everyone's trying to figure out how to stop Trump."
The election itself, on 8 November, will see America vote for a successor to Barack Obama, a Democratic president standing down after two terms in office which have seen the Republicans take control of both houses of Congress.