In his first public address as the Central Intelligence Agency chief, Pompeo said "it is time to call out WikiLeaks for what it really is: a non-state hostile intelligence service often abetted by state actors like Russia."
He said US intelligence services had found that Russian state-owned television network RT actively collaborated with the website.
Pompeo, a former Republican Congressmen who once applauded disclosures by WikiLeaks, said the intelligence community at CIA finds the celebration of entities like WikiLeaks "both perplexing and deeply troubling".
But his harshest words were directed at its founder Julian Assange, and at former NSA contractor Edward Snowden, who had leaked classified documents from the National Security Agency in 2013. "(They) seek to use that information to make a name for themselves" and "care nothing about the lives they put at risk or the damage they cause to national security".
More From This Section
Pompeo said Assange claims to harbour an overwhelming admiration for both America and the idea of America. "But I assure you that this man knows nothing of America and our ideals."
"When Snowden absconded to the comfortable clutches of Russian intelligence, his treachery directly harmed a wide range of US intelligence and military operations. Despite what he claims, he is no whistle blower. True whistleblowers use the well-established and discreet processes in place to voice grievances; they do not put American lives at risk," he said.
Pompeo said Assange's actions have attracted a devoted following among some of the most determined enemies.
"That Assange is the darling of terrorists is nothing short of reprehensible," he said.
Assange, an Australian citizen, has been living in the Ecuadorian Embassy in London. He received political asylum from the South American country after skipping bail to avoid extradition to Sweden, where he is wanted in connection with a rape case.
And Snowden lives at an undisclosed location in Russia after initially traveling to Hong Kong following his disclosure of the documents. Russia granted him asylum soon after.