Mr Biden said his team, while securing cooperation from some federal agencies, had “encountered obstruction from the political leadership” at the Pentagon.
“And the truth is that many of the agencies that are crucial to our security have incurred enormous damage,” he said on Monday local time.
“Many of them have been hollowed out — in personnel, capacity and in morale.
“There’s policy processes that have atrophied or have been sidelined to the despair of our alliances.”
Mr Biden‘s remarks came after he was briefed by members of his national security and defence teams and advisers, including his nominees for secretary of state, defence and homeland security, as well as his incoming national security adviser.
Incumbent administration slow to assist with transition, Biden says
Mr Biden takes office on January 20.
Last week, the Pentagon pushed back against the Biden team’s claims they had met resistance to requests for information.
A senior defence official said that the Pentagon had conducted 163 interviews and 181 requests for information and that it would continue to provide information and meetings.
But Mr Biden reiterated his team’s concerns.
“We’ve encountered roadblocks from the political leadership at the Department of Defense and the Office of Management and Budget,” Mr Biden said.
“Right now we just aren’t getting all of the information that we need from the outgoing administration in key national security areas.
“It’s nothing short, in my view, of irresponsibility,” he added.
When he takes office, Mr Biden will inherit a wide range of foreign policy and national security challenges, including China, Iran and North Korea, as well as the coronavirus pandemic raging across the globe.
One of his toughest tasks will be rebuilding US alliances that have frayed under four years of Mr Trump‘s “America First” agenda.
“My team needs a clear picture of our force posture around the world and our operations to deter our enemies,” Mr Biden said.
“We need full visibility to the budget planning under way at the Defense Department and other agencies in order to avoid any window of confusion or catch up that our adversaries may try to exploit.”