Trump denies telling Comey to back off, bashes former FBI director His first public comments since the announcement of a special counsel.

 -- President Donald Trump flatly denied that he asked former FBI Director James Comey to end his investigation into Trump's former national security adviser Michael Flynn.

Throughout a joint press conference with Colombian President Juan Manuel Santos, Trump repeated multiple times his claim that there was no collusion between himself and Russia during the campaign.

"There is no collusion between certainly myself and my campaign, but I can always speak for myself, and the Russians, zero," Trump told ABC News' Chief White House correspondent Jonathan Karl.

"Believe me -- there's no collusion. Russia is fine, but whether it is Russia or anybody else, my total priority, believe me, is the United States of America," Trump added.

He later reiterated: "There was no collusion, and everybody -- even my enemies have said, there is no collusion. So we want to get back and keep on the track that we're on."

Trump said that Comey "was very unpopular with most people" and said that he was expecting more widespread praise for the firing.

"But when I made that decision, I actually thought it would be a bipartisan decision. Because you look at all of the people on the Democratic side, not only the Republican side, that were saying such terrible things about Director Comey," Trump said.

"We need a great director of the FBI. I cherish the FBI. It is special. All over the world, no matter where you go, the FBI is special. The FBI has not had that special reputation with what happened in the campaign, what happened with respect to the Clinton campaign, and even you could say directly or indirectly with respect to the much more successful Trump campaign," he said.

Trump also said he "respects" the decision to appoint a special counsel to investigate the Trump campaign's ties to Russia, but he didn't distance himself from his earlier description of the situation as "a witch hunt."

"I respect the move, but the entire thing has been a witch hunt," Trump said.

He said that he thinks the appointment of a special counsel "divides the country."

"We want to bring this great country of ours together," he continued. "We have to get back to running this country really, really well."

Today marked the first time since the appointment of a special counsel that Trump publicly addressed Comey's firing and the subsequent news of a memo written by the ex-FBI director.

In the memo, which ABC News has not seen, Comey wrote that he was asked by the president to let the Flynn probe go in February. "I hope you can let this go," referring to the inquiry into Flynn's actions. "I hope you can see your way clear to letting this go, to letting Flynn go," said Trump, according to a source who read the memo. "He is a good guy. I hope you can let this go."

When Santos was asked if he had any suggestions for Trump on how to weather bad press, he demurred.

"I don't think I'm in a position to give any advice to President Trump. He can take care of himself," the Colombian president said.