Cory Booker is on the verge of leaving the Democratic presidential race, unless the New Jersey senator can raise an additional $1.7 million by Sept. 30, his campaign said Saturday morning.

Booker himself echoed that plea at the Polk County Steak Fry, a huge gathering of Democrats in Des Moines, Iowa, Saturday afternoon.

“I’m asking people to please support us now,” Booker told reporters, shouting over the roar of applause as Sen. Elizabeth Warren took the stage. "Now is the time we need. If you don’t have the money to compete in the fourth quarter, I don’t think you should be in this race.”

Campaign manager Addisu Demissie said that the late push is not a gimmick. Without enough money to build and sustain a campaign able to compete over the long term, he said, “Cory’s not going to continue running and consuming resources that are better focused on beating Donald Trump.”

The plea for donations came as the Democratic National Committee plans to increase the polling and fund-raising thresholds to qualify for televised debates beginning in November. Candidates who miss those contests are starved of attention, and several dropped out after missing the cutoff for the party’s debate earlier this month.

“Without a fund-raising surge to close out the quarter, we do not see a legitimate path going forward to win the nomination,” Demissie said in a conference call with reporters, echoing a memo the campaign had released early Saturday to supporters and the media.

He said the campaign has focused on building a strong staff in Newark and key early voting states, but needs more funding to realistically compete for the Democratic nomination. “We are asking clear as day for money, and without money you cannot build and without building you cannot win.”

As the call went on, Booker’s campaign blasted out fund-raising appeals by text and email.

>>READ MORE: How Cory Booker’s “failed” football career at Stanford shaped his political future

Coming just days before the deadline for the next fund-raising reports, often interpreted as a proxy for a campaign’s strength, the appeal drew skepticism, and some questioned whether it was just another appeal for money.

Booker’s campaign for months has argued that he is planning for the long haul and that it was too early to react to polls or consider Booker in any sort of political danger. Saturday, they said he essentially has a bit over a week to keep his campaign alive.

The senator had raised $9.6 million by the end of June, the latest figure available from the federal government. Now he is aiming to get 20% of that within 10 days.

Demissie said Booker has received a positive reception from Democratic voters, but that many people have not donated because they think it’s early or that he has enough resources to remain in the race. He argued that the choices will become far more narrow than voters realize unless Booker and others garner more support.

“The final field that is going to be offered to the Democratic Party come February, March, April, and beyond is being determined here in September,” Demissie said. “If you think Cory Booker should at the very least be a voice in this race and on this stage, then you should frankly lean in right now.”

Booker’s soaring speeches have been well-received in major campaign events, and he has won praise for his performances in the early presidential debates, but his message of unity and love has not translated into concrete gains. He has struggled to break beyond 1 or 2% support in national polls or in early states, and his fund-raising has lagged behind the top-tier candidates.

At the steak fry, Booker again delivered a stirring stump speech that had much of the crowd of 11,000 Democrats cheering enthusiastically for his message of unity. During the day he was one of the more accessible candidates, stopping for media interviews, flipping veggie burgers, and taking selfies with supporters, including Noelle Trevillyan, of Des Moines.

“I like him a lot," Trevillyan said. “I’d say he’s in my top six.”

Others asked about Booker said there was a lack of visibility in Iowa, compared to the other campaigns, despite the recent growth of his campaign staff there. “I haven’t seen much of him,” said Ellen Kroeker, who supports Castro and Warren. “I think he hasn’t caught fire because he’s kind of unknown, to be honest.”

Steve Laird drove up from Kansas City to see Booker speak.

“It’s difficult, I have friends ... who poke fun at me about it," Laird said of supporting a longer-shot candidate. “But I don’t pick a candidate because I think they’re gonna win. Chances are difficult. His back is against the wall and when I heard he was considering dropping out it made my knees buckle a little but he’ll fight and that’ll make us work harder for him.”

>>READ MORE: At Philly rally, people say they like Cory Booker — but aren’t so sure about his chances

Booker has tried to win over voters with a focus on inspiration and his biography, then a reset to policy, then a confrontation with Joe Biden on race, then with a return to a call for togetherness, all without changing his trajectory. Monmouth University pollster Patrick Murray has referred to Booker as being in voters’ “friend zone,” well-liked, but not a first love.

After one August event in Philadelphia, voters raved about his speech but questioned if he could win.

One challenge has been standing out in a crowded and diverse field that includes several other people of color, and several other senators also in their 50s.

>>READ MORE: Cory Booker, in Iowa for his first campaign stop, pitches inspiration over ideology

Booker also has other political considerations. His Senate term is up next year, meaning that eventually he will have to choose which campaign to prioritize. New Jersey law was recently changed to allow him to run for reelection and president at the same time, but it might be difficult to pitch himself as the Democratic nominee while also seeking a fall-back job.

Staff writer Julia Terruso contributed to this article.