Elections officials across the country are accelerating their efforts to install ballot drop boxes, a move they hope will make absentee voting simple and safe for those wary of the mail or fear exposure to the novel coronavirus at polling places.

The efforts come as voters voice concerns about timely delivery of mail ballots. Already, postal workers are reporting days-long backlogs of mail across the country, calling into question whether ballots will arrive at elections offices in time to be counted in November. President Trump has also ramped up attacks on the integrity of mail voting, in a year when more voters than ever are expected to choose that method because of the pandemic.

But the use of these boxes — which often look similar to a mailbox and are typically under video surveillance or guarded — has come under attack in states newly adopting them this year. Some skeptics worry the boxes may not be properly monitored to prevent tampering, or that voters will not know how to use or find them. In the battleground state of Pennsylvania, these drop boxes are now in the center of a Trump campaign lawsuit raising similar concerns.

Some see drop boxes as a safer and more reliable way to cast ballots than the mail. For instance, Michigan elections officials urged absentee voters to use drop boxes rather than the Postal Service after mail delivery backlogs led some to receive their ballot as late as one day before Tuesday’s primary election.

“Once it leaves the voter’s hand, the elections official has no control over it until it’s back in their hand. I think that’s why these drop boxes give them a little bit more of a sense of ... ‘If you put this in the drop box by the appropriate time on Election Day, it’s going to count,’ ” said Matthew Weil, director of the Bipartisan Policy Center’s Elections Project. “That’s a good feeling for an elections official, and I think voters should feel confident in that option, too.”

In the District of Columbia, election officials resorted to hand-delivering ballots that were at risk of not arriving on time for the June 2 primary. The Board of Elections is now looking to hire a vendor to provide up to 50 boxes that will be available for ballot drop-off until 8 p.m. on election night in November.

“We know we have voters who are uncomfortable with the mail, and some voters have informed us that their mail is not regularly picked up or received on either end,” said Alice Miller, the executive director of the D.C. Board of Elections.

But some lawmakers and state officials have raised concerns about the security of these boxes.

In Tennessee, for example, the Republican state secretary of state last month voiced his opposition to offering drop boxes, saying during a U.S. Senate hearing that he is worried about potential coercion among those who want to deliver ballots on behalf of voters.

In Pennsylvania, where the governor had extended the deadline for voters to drop off mail ballots in the June 2 primary in several counties with high coronavirus infection rates, the Trump campaign and the Republican National Committee filed a lawsuit seeking changes for the November election.

The lawsuit, filed in the U.S. District Court for the Western District of Pennsylvania, alleges that Pennsylvania Secretary of the Commonwealth Kathy Boockvar (D) and other election officials did not properly monitor the boxes during the primary to make sure they were not vulnerable to fraud. While the lawsuit does not allege any specific fraud, it asks the federal court to ban the use of drop boxes in the fall, or allow poll watchers to guard the boxes.

In a statement, the Trump campaign said they were concerned about the last-minute election changes enacted by the state’s Democratic leaders and that they open up the potential for fraud.

“Shifting from an absentee voting system to one that pushes unmonitored vote-by-mail creates opportunities for fraud, and encourages ballot harvesting where paid political operatives try to collect and deliver loose ballots,” said Jenna Ellis, Trump 2020 campaign senior legal adviser, in a statement.

“This lawsuit seeks to restore integrity into the process and mandate the ability of campaigns to monitor the casting, collecting, and counting of all votes. Every American, regardless of which candidates they support, should be concerned that our elections remain free and fair,” the statement read.

Boockvar’s office declined to comment, citing ongoing litigation.

Elections officials nationally say they are confident in the security of drop boxes, noting that several states have used them for many years without trouble, and that there is a rigorous process of making sure the voting method is secure and safe.

In South Carolina, state elections officials are already working on plans to protect voters while they urge lawmakers to approve the use of drop boxes. For example, they are planning to audit the ballots that were dropped off, and drop-offs would only be possible during business hours.

“If they were trying to attempt some type of fraud . . . they would get caught very quickly in South Carolina,” said Katy Smith, president of the South Carolina Association of Registration and Election Officials.

The Election Assistance Commission, an independent federal agency that helps local and state officials administer elections, recommends that states newly adopting drop boxes make sure the boxes are properly protected from tampering, and hire bipartisan teams of workers to pick up and transport the ballots to elections offices regularly throughout the day.

The box itself must be locked or have a tamper-evident seal and permanently affixed if it is located outdoors, the guidance says. There should be a chain of custody and close documenting of the pickups, and either staff monitoring or video surveillance, according to the guidance.

The commission also warns states to check their state laws regarding whether voters can designate other people, such as their family members, to drop off ballots on their behalf.

In Georgia, elections officials decided this year to use drop boxes for the first time, and more than 200 boxes have been set up across the state. The state rule required physical or camera security, and in one county, the video surveillance is monitored by the police department, said Jordan Fuchs, Georgia’s deputy secretary of state.

Nearly every county in Georgia now has a drop box. The state is distributing up to $3,000 in federal grants for each of its 159 counties so they can increase the number of boxes and take steps to make sure they are protected and monitored, Fuchs said.

“The absentee ballot drop boxes provide a secure and reliable way for voters to cast their ballots without worrying about their health,” Fuchs said. “When they drop absentee ballots in the drop box before the deadline, they can be sure that their ballot was received by election officials. When they put the ballots in the mail, the delivery of their ballots on time is no longer in their control.”