(Bloomberg) -- President-elect Joe Biden said a major hack of U.S. government agencies and companies isn’t being taken seriously enough by President Donald Trump and that he’ll prioritize strengthening America’s cyber defenses.

The attack “happened on Donald Trump’s watch,” Biden said Tuesday at a news conference in Delaware. “We can’t let this go unanswered.”

Biden called for cyber threats to be treated the same as attacks undertaken using other unconventional weapons and said he’d seek bipartisan support for his efforts after taking office Jan. 20.

Saying that Trump is still president for almost another month, Biden said it’s the president’s job to lead the country through the crisis and called on the current administration to call Russia out over the hack.

After his own officials suggested Russia was behind the hack, Trump tweeted that China was perhaps responsible for the attack. In making his case, Biden cited comments by Secretary of State Michael Pompeo and Attorney General William Barr, who both said the evidence points to Russia. And Biden vowed to respond.

“We will respond and respond in kind,” Biden said.

Russia has denied having any role in the hack.

The attack, which took place over several months starting this year, targeted updates in widely-used software from Austin, Texas-based SolarWinds Corp.

The company sells technology products to entities including the State Department, the Centers for Disease Control and Prevention, the Naval Information Warfare Systems Command, the FBI, the U.S. military and most Fortune 500 companies, according to the company’s website and government data.

So far, a number of state governments, the city network in Austin, the U.S. nuclear weapons agency and software giant Microsoft Corp. have reportedly had their systems exposed by the attack.

©2020 Bloomberg L.P.