Former President Barack Obama joined Angela Alsobrooks, the Democratic candidate for Maryland's Senate seat, at a phone banking session on Thursday, according to the Alsobrooks campaign.

The visit comes just days before the general election, and on the last day of early voting in Maryland, where Alsobrooks' Republican opponent is the state's former governor Larry Hogan.

While the race has been seen as competitive even in relatively blue Maryland, Alsobrooks has held a lead in polling.

“President Obama knows what is at stake in this election,” Alsobrooks said in a press release. "And I am so grateful he’s joined our phonebank today to urge voters to get out and vote to defend our Democratic Senate Majority in order to protect our freedoms, fight for our futures, and ensure our families can thrive."

Maryland Attorney General Anthony Brown sent a cease-and-desist letter to the Washington, D.C.-based Center for Voter Information/Voter Participation Center, alleging that it has been threatening to publicly expose registered voters who don’t vote in this year's election.

Brown has requested that the organization refrain from publishing voter information or attempting to embarrass non-voters.

In the cease-and-desist letter, he wrote, "Voting is among the most important rights that Marylanders have. Any action that intimidates prospective voters, especially on the eve of such a consequential election, will not be tolerated."

"These unnerving letters are unacceptable, and Maryland voters should know that their decision to vote this Election Day is entirely theirs to make," he continued.

The organization mass-mailed letters to Maryland residents that stated, "We’re sending this mailing to you and to your neighbors to share who does and does not vote in an effort to promote election participation. While we have hidden the name and street number of your neighbors to protect privacy, these are true voting records."

"We will be reviewing these records after the election to determine whether or not you joined our neighbors in voting," the organization's letters said.

As Indiana surpasses 1 million early voters this election, state Republicans have blocked the expansion of early voting in one of the state's biggest counties.

The Marion County Election Board blocked a motion Thursday to keep early voting locations open two hours longer on Friday, Saturday and Sunday due to long lines throughout the county.

Marion County, the state’s most populous county, is home to Indiana’s capital.

With long lines across the state, Indiana Democrats told ABC News they had hoped voters would have more time to vote this weekend.

"Republicans in Indiana are becoming experts at disenfranchising voters," Indiana Democratic Party Chair Mike Schmuhl said. “We’ve seen long lines in Indianapolis and across the state because Hoosiers are excited to vote in this election."

"This is something voters want. They do not want to wait in lines, or can’t afford to, even in the best weather," he added.

-ABC News' Beatrice Peterson

Gov. Tim Walz made a campaign stop at Vilma's Kitchen, a local Puerto Rican restaurant in Erie, Pennsylvania, on Thursday and brought up the controversial joke about the island from Trump's Madison Square Garden rally.

Walz said the comedian's insult was "incredibly hurtful" and "dangerous."

"We saw what happened in New York City and Madison Square Garden, as another attempt to divide us," he said.

Walz also told the group that the country needs a “specific Puerto Rico strategy.”

"I say this as a teacher, we've got to educate our fellow Americans about our fellow citizens in Puerto Rico, why it's important [and] why we're investing there, and then understanding how much the Puerto Rican community contributes to all of our states across here," he said.

Walz also spent time meeting with members of the Bharatiya Temple in Montgomery County, Pennsylvania, as they celebrated Diwali.

Walz thanked the Indian and South Asian community for their contribution to "all aspects of civil, political, educational” life, in addition to their input ”across the arts and entrepreneurship and business."

"To see the political voice rise itself up, [and] to see us elect folks that look like the community, we get a more perfect union that way," he said.

-ABC News' Isabella Murray