Republican Texas Senator Ted Cruz, locked in a tight race in Iowa with Donald Trump just two days before the state's crucial US presidential nominating contest, has urged supporters to give him the first victory of the 2016 campaign.
Ten Republicans and three Democrats were campaigning in Iowa for their parties' nominations but much of the focus was on the fight between Cruz and Trump.
"This is your time," Cruz told a crowd of about a thousand at a hotel ballroom.
"This is the time for the men and women of Iowa to make a decision. We are inches away."
On Monday (local time), Iowans will gather in homes, gymnasiums, libraries, taverns and even grain elevators for caucuses to select their favourite for the Democratic and Republican presidential nominations. When they are finished, the race will take on a new dynamic and several candidates are expected to drop out altogether.
Polls suggest that either Cruz, who is making a furious last-minute swing through as many counties and small towns as he can, or Trump, who was holding several large-scale rallies across Iowa this weekend, will prevail among the Republicans.
Trump used stagecraft and blasted Cruz to enliven a crowd in Dubuque as he barnstormed through eastern Iowa.
At the airport, Trump's plane, with his name emblazoned on the side, did a fly-by near the hangar where he was to soon speak.
The plane landed, and he emerged from his plane to speak to a crowd of about 400, small by Trump standards.
Trump urged people to caucus.
"This is now crunch time," he said.
While at his event in Ames, Cruz refrained from attacking Trump but the New York developer was not so circumspect. He continued to suggest that Cruz may not be legally qualified to be president because he was born in Canada.
"How the hell can you run for president?" Trump said. "Ted has a big problem."
On the Democratic side, Hillary Clinton, the former Secretary of State, and Vermont Senator Bernie Sanders remain engaged in a fierce battle, both in Iowa and elsewhere.
The two, along with former Maryland Governor Martin O'Malley, agreed in principle to add four debates to their calendars, Clinton's campaign said.
The first will be next week in New Hampshire, contingent on approval by the Democratic National Committee.
The Clinton campaign also called for a debate in Flint, Michigan, to highlight the city's water-contamination crisis.
Clinton made a stop as well in Ames, where she spoke to a crowd of more than 1100 at Iowa State University.
She was introduced by former US Representative Gabby Giffords and her husband, former astronaut Mark Kelly.
In 2011, Giffords was critically injured when she was shot during an assassination attempt near Tucson, Arizona. In her remarks, Clinton praised gun-control measures recently taken by US President Barack Obama.
"None of it will stick if it's not a voting issue, and as you go to caucus Monday night, please think about this," Clinton said.