MANCHESTER, N.H. -- Bernie Sanders held a narrow lead over Pete Buttigieg in the New Hampshire Democratic primary Tuesday night as the two men from different generations and wings of their party battled for front-runner status in the chaotic nomination fight to take on President Donald Trump.

After essentially tying in Iowa last week, the strong showings from Buttigieg and Sanders cemented their status at the top of the 2020 Democratic field. And an unexpectedly strong performance from Amy Klobuchar gave her a stronger path out of New Hampshire as the contest moves on to the gauntlet of state-by-state primary contests that lie ahead.

The strength of Sanders and Buttigieg was matched in reverse by the struggle of former Vice President Joe Biden, who spent most of the last year as the Democrats' national front-runner but left New Hampshire hours before polls closed anticipating a bad finish. With final returns ahead, he was competing for fourth place with Elizabeth Warren, a disappointing turn for the senator from neighboring Massachusetts.

Neither Biden nor Warren was on track to receive any delegates.

With votes still coming in, the race was too early to call. But the front-runners were cheerleading and being cheered by their supporters.

Democratic presidential candidate former South Bend, Indiana, Mayor Pete Buttigieg meets with people outside a polling place where voters will cast their ballots in a primary election Tuesday in Manchester, New Hampshire.Matt Rourke ~ Associated Press

"So many of you chose to meet a new era of challenge with a new generation of leadership," Buttigieg said.

Sanders boasted of "a movement from coast to coast ... to defeat the most dangerous president."

The New Hampshire vote made clear that the early days of the Democratic contest will be a battle largely between two men who are four decades apart in age and are ideological opposites. Sanders is a leading progressive voice, calling for a substantial government intervention in health care and other sectors of the economy. Buttigieg has pressed for more incremental changes, giving Americans the option of retaining their private health insurance and making a point of appealing to Republicans and independents who may be dissatisfied with Trump.

Yet Sanders and Buttigieg enter the next phase of the campaign in different political positions.

While Warren made clear she will remain in the race, Sanders, well-financed and with an ardent army of supporters, is quickly becoming the leader of the progressive wing of the party.

Democratic presidential candidate Sen. Amy Klobuchar, D-Minn., speaks at her election night party Tuesday in Concord, New Hampshire.Robert F. Bukaty ~ Associated Press

Meanwhile, Buttigieg still has moderate rivals to contend with, including Klobuchar, whose standout debate performance led to a late surge in New Hampshire. Biden promises strength in upcoming South Carolina, while former New York Mayor Mike Bloomberg was not on Tuesday's ballot but looms next month.

Biden, after dismal performances in Iowa and New Hampshire, is staking his candidacy on a strong win Jan. 29 in South Carolina, which is the first state with a substantial black population to weigh in on the Democratic race.

After a chaotic beginning to primary voting last week in Iowa, Democrats hoped New Hampshire would provide clarity in their urgent quest to pick someone to take on Trump in November. At least two candidates dropped out in the wake of weak finishes Tuesday night: just-the-facts moderate Colorado Sen. Michael Bennet and political newcomer Andrew Yang, who attracted a small but loyal following over the past year and was one of just three candidates of color left in the race.

While struggling candidates sought to minimize the latest results, history suggests that the first-in-the-nation primary will have enormous influence shaping the 2020 race. In the modern era, no Democrat has ever become the party's general election nominee without finishing first or second in New Hampshire.

The action was on the Democratic side, but Trump easily won New Hampshire's Republican primary. He was facing token opposition from former Massachusetts Gov. Bill Weld.

Warren, among the front-runners for months, offered an optimistic outlook as she faced cheering supporters, "Our campaign is built for the long haul, and we are just getting started."

Despite an embarrassing defeat that raised questions about her path forward, Warren vowed to trudge on.

"Our campaign is built for the long haul, and we are just getting started," she declared.

Having already predicted he would "take a hit" in New Hampshire after a distant fourth-place finish in Iowa, Biden essentially ceded the state. He was traveling to South Carolina Tuesday as he bet his candidacy on a strong showing there later this month boosted by support from black voters.

More than a year after Democrats began announcing their presidential candidacies, the party is struggling to coalesce behind a message or a messenger in its desperate quest to defeat Trump. That raised the stakes of the New Hampshire primary as voters weighed whether candidates were too liberal, too moderate or too inexperienced -- vulnerabilities that could play to Trump's advantage in the fall.

He was not on the ballot, but Bloomberg, a New York billionaire, loomed over the New Hampshire contest as moderates failed to embrace a single alternative to Sanders.

Bloomberg was skipping all four states that vote this month in favor of dozens of delegate-rich contests in March. He's already devoted hundreds of millions of dollars to the effort.

Sanders and Buttigieg were on track to win the same number of delegates with most of the vote tallied, and Klobuchar a few behind. Warren, Biden and the rest of the field were shut out, failing to reach the 15% threshold needed for delegates.

AP has allocated six delegates each to Sanders and Buttigieg and four to Klobuchar with eight still to be called.

After Iowa and New Hampshire, Buttigieg held a one delegate lead over Sanders with one Iowa delegate yet to be allocated and Buttigieg leading ever so slightly in that contested count. Klobuchar now joins a close knot in a second tier with Warren and Biden, about ten delegates behind the two leaders.

Democrats were closely monitoring how many people showed up for Tuesday's contest. New Hampshire's secretary of state predicated record-high turnout, but if that failed to materialize, Democrats would confront the prospect of waning enthusiasm following a relatively weak showing in Iowa last week and Trump's rising poll numbers.

The political spotlight quickly shifts to Nevada, where Democrats will hold caucuses on Feb. 22. But several candidates, including Warren and Sanders, plan to visit states in the coming days that vote on Super Tuesday, signaling they are in the race for the long haul.

Peoples reported from Washington. Associated Press writers Seth Borenstein in Washington, Will Weissert, Holly Ramer and Thomas Beaumont contributed from New Hampshire.

Catch up on the 2020 election campaign with AP experts on our weekly politics podcast, "Ground Game."