Donald Trump has been mocked by his Republican rivals at a televised debate in Iowa, after quitting the event in a row with Fox News.
He decided to withdraw after the broadcaster refused to drop host Megyn Kelly, whom Mr Trump accused of bias.
The debate began with his rival Senator Ted Cruz marking his absence by throwing mock insults at the others.
The billionaire businessman held a charity rally nearby, in honour of the country's war veterans.
But his absence on the stage in Des Moines, where seven of his rivals in the race to be Republican presidential nominee, was keenly felt.
Mr Cruz addressed it with humour in the opening minutes of the debate.
"I'm a maniac and everyone on this stage is stupid, fat and ugly, and Ben [Carson], you're a terrible surgeon," he said, doing an impression of his absent rival.
Former Florida Governor Jeb Bush also poked fun at the billionaire businessman, who has often tormented Mr Bush in previous debates.
"I kind of miss Donald Trump; he was a teddy bear to me," he said with smile.
- Florida Senator Marco Rubio stood by previous pledge to shut down mosques where radicalisation is taking place
- He also promised to tear up the nuclear deal with Iran on "day one" of being president
- Texas Senator Ted Cruz said: "I will hunt down Isis [IS] wherever they are and completely destroy them"
- Retired neurosurgeon Ben Carson said he has had "more 2am phone calls than anyone else here", making life or death decisions
- New Jersey Governor Chris Christie said he would get government working for people again
- Ohio Governor John Kasich says he would "get everyone together" of all religions to defeat Islamist radicals
- Ex-Florida Governor Jeb Bush says the country's veterans deserve greater respect than they get in Obama's US
- Kentucky Senator Rand Paul raised concerns about the US expanding military role in Syria
Elsewhere in Des Moines at the same time, Mr Trump led a raucous rally in honour of the country's war veterans.
"When you're treated badly, you have to stick up for your rights," he said, referring to his row with Fox.
"We have to stick up for ourselves as people and we have to stick up for our country if we're being mistreated."
Many observers on social media thought the event missed the brash New Yorker but others remarked how not having his dominating personality to contend with was a positive.
In polls, Mr Trump is currently leading the Republican pack in Iowa with 33.2 percent of the vote (6.5 percentage points above his nearest rival, Texas Senator Ted Cruz), and is in the lead nationally with 36.2 percent (16.8 points over Mr Cruz).
The Republican field is a wide one, and a debate undercard featuring four of the lowest-polling candidates was held earlier on Thursday evening.
The Iowa caucuses on Monday were seen as the first real test of the election campaign, and the beginning of a series of state-by-state contests to chose delegates for both Republicans and Democrats.
Unlike a primary, which is a traditional election featuring secret ballots on polling day, the caucuses in Iowa is a meeting of registered party voters and activists where they discuss the candidates and then vote.
Voters in Iowa on Monday are due to pick their presidential nominee for each party.