Democratic senators are asking a federal agency that helps certify and secure voting systems for a “full account” of its work to secure the 2016 election from Russian hackers.

The senators, led by Amy Klobuchar (D-Minn.), also want the Election Assistance Commission (EAC) to detail cybersecurity challenges facing state and local officials as they look to safeguard future elections.

The intelligence community concluded in an unclassified report released in January that Russia engaged in a cyber and disinformation campaign during the election to undermine U.S. democracy and damage Democratic nominee Hillary Clinton.

Intelligence officials determined that “Russian intelligence accessed elements of multiple state or local electoral boards,” though they found no systems involved in voting tallying were breached.

Nearly all 50 states asked for help from the Department of Homeland Security to secure their voting systems ahead of the presidential election, following reports that election databases in Illinois and Arizona had been breached by hackers.

The EAC certifies voting systems and helps state and local election officials make sure elections are accurate and secure. In December, the commission said it was investigating a possible cyberattack on its web-facing systems.

“We are writing to request a full account of the EAC’s efforts in the cybersecurity sphere in 2016,” the senators wrote in a letter to the commissioners, according to a Friday release.

“Based on your work with election officials, cybersecurity experts and federal law enforcement, we also would appreciate an impartial assessment of the challenges that state and local election officials face in protecting future U.S. elections from cybersecurity threats,” they wrote.

Twenty-six senators, including Independents Angus King (Maine) and Bernie Sanders (Vt.), signed onto the letter.

The lawmakers expressed “deep concerns” about potential Russian interference in future U.S. elections and the federal government, alluding to former national security adviser Michael Flynn’s contact with Russian Ambassador Sergey Kislyak, which forced Flynn to resign from his post earlier this month.

They also underscored the need to make future cybersecurity upgrades to voting systems in order to ensure their security.

“As motivated and sophisticated cybercriminals will continue to target our election systems, we must ensure that our state and local election administrators have the resources they need to make critical cybersecurity upgrades,” the senators wrote.

“Aging machines are vulnerable to hacking since they lack the latest security features. In 2016, 43 states used electronic voting machines that were at least 10 years old,” they wrote. “While there was no reported damage to actual voting machines or voter registration data last year, we hope you will agree when we say that the 2016 election was a wake-up call. We must do more to protect our U.S. elections from foreign interference.”

The senators asked the commissioners to describe “the full extent of foreign interference and hacking that occurred in any national, state or local election system” during the November election, in addition to a series of other questions.