Former U.S. Vice President Joe Biden, 2020 Democratic presidential candidate, speaks while his wife Jill Biden listens during a caucus night watch party in Des Moines, Iowa, U.S. on Monday, Feb. 3, 2020.

Joe Biden's campaign tried to reassure donors on Tuesday that the former vice president is on track to win the Nevada caucus and the South Carolina primary, just a day after the Iowa caucus was derailed by vote-counting glitches.

On a conference call with some top donors just hours after the Iowa contest concluded, campaign officials said they were confident they can win the two votes scheduled for the end of the month, according to people familiar with the call, who declined to be named as the conversation was deemed private.

The call left the donors feeling positive about Biden's efforts in those two states, according to the people. The Nevada caucuses are set for Feb. 22, and the South Carolina primary is a week later.

While official results hadn't been released Monday night or Tuesday morning, there were reports and entrance polling data suggesting that Biden had not performed as well as his top three rivals, Sens. Bernie Sanders and Elizabeth Warren and former South Bend Mayor Pete Buttigieg.

Biden's advisors stressed to donors that they're not convinced Buttigieg won the Iowa caucuses, despite his claim Monday night, these people added. They also pushed the notion that turnout wasn't as high as Sanders had hoped for. An NBC News entrance poll shows that turnout was slightly below 2016's total.

Biden aides started sharing similar sentiments to donors late Monday, the people familiar with the matter added.

The Iowa Democratic Party has been under scrutiny since the delay of releasing the data that would show who won the caucuses. The state party released a statement on Tuesday saying its on track to release much of the results Tuesday and acknowledged that a technical glitch was the cause for the delay. Party leaders in the state told campaigns on Tuesday they will release the majority of the results by 5 p.m. ET on Tuesday.