"We have to find the people that are working against this administration and they need to be purged from this community," the Iowa Republican told CNN's Alisyn Camerota on "New Day."
"We need to find out who the leaking moles are who are violating federal law because we can't function from a national security standpoint if we have that spillage coming out of the community," he added.
High-level advisers close to Donald Trump were in constant communication during the campaign with Russians known to US intelligence, multiple current and former intelligence, law enforcement and administration officials told CNN.
Prior to Trump entering the White House, he and former President Barack Obama were both briefed on details of the extensive communications between suspected Russian operatives and people associated with the Trump's campaign and business, according to US officials familiar with the matter.
Chairman of the Select Committee on Intelligence Devin Nunes has already said he'll look into the leaks.
King, who supported Trump during the election, said people from the intelligence agencies going to the media about members of the Trump campaign being involved in potentially illegal activity could harm Americans.
"We're at great risks if we have these kinds of moles with this low level of integrity that are leaking information out to move their political agenda," he said. "It's unpatriotic and it's an act that undermines our American security."
King accused those leaking information as being motivated by a lack of support for Trump opposed to concerns that those associated with the President jeopardized national security.
"There are opinions in the intelligence community that are the direct enemies of Donald Trump that don't want him to succeed," he said.
"I think what is most important here is the leaks coming out of the intelligence community that appear to be designed to politically assassinate members of the Trump Administration and at least weaken the Trump Administration."
Retired Lt. Gen. Michael Flynn resigned as Donald Trump's national security adviser after intelligence revealed that he had misled Trump and Vice President Mike Pence regarding his conversations with a Russian ambassador before Trump entered the White House.