Image copyright AP Image caption Bernie Sanders' focus on international trade swayed many voters

Although the latest primary and caucus elections highlighted Donald Trump's continuing march to the Republican nomination for the US presidency, many in the US media chose to focus on the shock win for Bernie Sanders in the Democratic battle in Michigan.

The New York Times, Washington Post, Los Angeles Times and Huffington Post were among those leading their online coverage with Mr Sanders' victory over Democratic front-runner Hillary Clinton there.

Many writers suggested the issue of international trade deals had swayed blue-collar voters, many of whom believe such agreements have cost American jobs.

But while the victory is seen as invigorating Mr Sanders' campaign, many also point to Mrs Clinton's huge win in Mississippi. This has given her an overall victory in the number of delegates secured on the night.

Cash donations

Sam Frizell writing in Time magazine said Mr Sanders' win "in the large, demographically diverse state with a big manufacturing base is crucial for the survival of his campaign, and he proved with his Tuesday night coup that he can still win a hard-fought contest despite lagging in the overall delegate count".

Ben Geier, writing for Fortune, says Mr Sanders' victory has "changed the race for the Democratic nomination".

He adds: "He will likely be able to use this win to get another round of fundraising, as most of his donors are individuals who haven't maxed out their donation totals; if they gave $10 in October, he can ask them to give another $10 now. And given the general enthusiasm of Sanders voters, it's a good bet a lot of them will."

Image copyright Reuters Image caption Hillary Clinton may need to "rethink her economic message"

The Washington Post says the Michigan result "raises the stakes for a candidates' debate on Wednesday from delegate-rich Florida", which holds its primary next Tuesday.

Yamiche Alcindor and Patrick Healy in the New York Times, write that Mr Sanders' "startling upset" in Michigan came by "hammering Mrs Clinton on an issue that resonated in this still-struggling state: her past support for trade deals that workers here believe robbed them of manufacturing jobs".

They add: "For Mrs Clinton, it was a stinging defeat... a reminder of her weakness among two key voting blocs: working-class white men and independent voters. The setback will almost certainly lead her to sharpen or even rethink her economic message, which does not seem to be reaching voters who feel betrayed by the Democratic Party's embrace of free trade and left behind by the forces of globalisation and deregulation."

John Cassidy, in The New Yorker, writes that although Mr Trump and Mr Sanders differ wildly, "they both claim that the existing political system is broken, and that radical measures and new leaders are needed to fix it".

"If this message were to prove equally successful in other industrial states, such as Ohio, Pennsylvania, and Wisconsin, it would have big implications for the general election in addition to the primaries."

He says that although it appears Mr Sanders' chance on closing the delegate gap with Mrs Clinton "appears slim", he "could remain competitive until the big primaries in New York and California, where he is hoping to pull off more upsets. This calculus may seem unlikely. Until last night, however, it seemed unlikely that he would win in Michigan".

Alex Seitz-Wald, for MSNBC, writes that Mr Sanders' "advisers had long predicted the beginning of March would be rough for them, thanks to the high concentration of southern states with large African-American populations that so far have favoured Clinton by wide margins.

"But with those states now in the rear view mirror, Sanders' campaign expects to sail into friendlier waters later in the month, beginning next Tuesday (when votes are held in Florida, Illinois, Missouri, North Carolina and Ohio)."