After federal immigration agents shot and killed two U.S. citizens in Minneapolis early this year, Kristi Noem, the homeland security secretary at the time, pledged that the government would “rapidly acquire and deploy” body cameras on agents across the country.

But after immigration officers fatally shot two people during enforcement operations over the past week, the Department of Homeland Security disclosed that none of the officers involved wore body cameras.

The killings have drawn fresh scrutiny of the delayed deployment of body cameras, whose video evidence can be key to investigations.

Body cameras have been deployed to more than half of Immigration and Customs Enforcement field offices, with the remaining half set to receive them in the next 60 days, a D.H.S. spokesperson said in a statement on Tuesday. The statement said that ICE now had “historic funding” for the resources it needs, including body cameras, citing a bill Congress passed last month giving the department an additional $70 billion for immigration enforcement over several years.

But the issue of who is responsible for the delay has devolved into a partisan blame game.

Senator Susan Collins, Republican of Maine, said in a social media post on Tuesday that it was “extremely unfortunate” that the agent involved in the shooting in Biddeford, Maine, this week was not wearing a body camera. She and the Department of Homeland Security said that Democratic lawmakers were at fault for forcing the agency’s shutdown earlier this year, delaying the deployment of body cameras. The 76-day shutdown began in mid-February after Democrats refused to fully fund the department without new restrictions on ICE officers, including requiring them to unmask themselves during operations and obtain judicial warrants to enter homes.

“The process of purchasing and issuing body-worn cameras to all of our ICE field offices was interrupted by the Democrats’ multiple government shutdowns,” the D.H.S. statement said.

Democrats said the department was flush with billions in federal funding from the domestic policy bill that Republicans passed last summer, giving it ample time and money to equip immigration officers with cameras.

“Last summer, Republicans provided ICE with tens of billions of dollars in funding that could have been used to deploy body cameras nationwide,” Senator Patty Murray of Washington, the top Democrat on the Appropriations Committee, said in a statement.

Congress also approved $20 million in funding specifically for the expansion of body camera use as part of a spending bill it passed in April.

Democrats pushed back on the assertion that the deployment had been delayed because of the record-long shutdown earlier this year.

“The idea that Democrats are to blame for the Trump administration’s failure to deploy body cameras to the field and to protect people from out-of-control agents that they have failed to properly train is completely absurd,” Ms. Murray added. “The problem has not been funding; ICE has more money than most modern militaries. It’s been this administration’s refusal to quickly put in place basic accountability measures like requiring body cameras.”

Catie Edmondson contributed reporting.