(CNN) Rudy Giuliani vigorously defended his business ties with foreign governments and the work his law firm did for foreign clients and countries in an interview with CNN's KFile Friday.

The former New York City mayor is considered a top pick to be President-elect Donald Trump's secretary of state, but reports of his past consulting work for foreign governments, including in Qatar and Serbia, have raised conflict of interests concerns should he be chosen.

In a phone interview with CNN, Giuliani cast his work, which included consulting work on reducing crime in Mexico City, El Salvador, Colombia, Chile, along with helping political candidates in Ukraine and the Dominican Republic, as a qualification to be secretary of state. The former New York City mayor also sought to rebut critics who say that his consulting and speeches make his attacks on the Clinton Foundation during the presidential campaign hypocritical.

"What I did violated no laws, no regulations," Giuliani said. "It was a perfectly legal, lawful, thing to do. And also these comparisons to Hillary Clinton are nuts because I was in private business. I was not—there's no conflict with anything. I'm not a government official. I'm in private business. And finally, I wasn't selling influence. I was selling my expertise. And the services of my company.

Giuliani contacted CNN in response to a story by CNN's KFile about his 2012 work consulting with Serbian politicians once tied to convicted war criminal Slobodan Milošević. Giuliani said he was providing development advice to the city of Belgrade. In interviews at the time, Giuliani said he was there "to give advice" to Aleksandar Vucic, now the Serbian prime minister, who was running for mayor at the time. Giuliani said that he was paid by a London company involved in putting together a plan for economic development in Belgrade. Press reports at the time cited Vucic saying he had invited Giuliani to advise him.

In the interview Friday, Giuliani said that he was invited by the London company and that his team had assessed the offer and determined that they could provide useful advice to the city. He also defended the content of his consultation.

"I didn't go in there and give a public relations address," he said. "I went there and gave a highly substantive speech on what happens to be one of the areas of knowledge which is perfectly lawful. I don't know what it is that I did wrong. Or how you can paint it is as wrong."

"I conducted myself in a very honorable way. Including a somewhat courageous way, to add, yeah, 'I think you should've been bombed,'" Giuliani also said, referring to NATO's bombing of Yugoslavia. "How many people go to a city and say, 'I think it was okay you were bombed. You know how often I've done that?"

Giuliani further cited his relationship with Viktor Yushchenko, the former Ukrainian president and foe of Vladimir Putin who was poisoned in 2004. He said that when he went to Ukraine, he was told that he couldn't meet with Yushchenko (Giuliani misspoke and said he couldn't meet with Viktor Yanukovych, another former Ukrainian president and a Putin ally, but described him in the interview as "the Viktor that Putin poisoned or allegedly poisoned"). The former mayor said that he met with Yushchenko anyway.

"I said, 'F*ck you, I'll meet with him,'" he said. "And I did. And they took away my security and almost didn't let me out the country. And that's before the poor man was poisoned. He and his wife have become good friends of mine. And what I am upset about is the attacks on my reputation."

In the conversation, Giuliani often returned to the idea that his work gave him foreign policy knowledge that would be valuable if Trump picks him as secretary of state, arguing that he is being unfairly "hit on both ends," referring to critics who say he lacks experience and those who say he may be hampered by conflicts of interest.

"I know all these governments," Giuliani said. "I know the good parts and the bad parts. When I go, I often meet with the prime minister, if I don't meet with the prime minister I always meet with the interior minister and almost always with the defense minister. They want my advice, because I have substantive expertise. They don't want my influence, nor did they try to ask me to influence President Obama which would be ridiculous of course or even President Bush. I'm not seen that way. I'm not seen as a lobbyist, government influencer. I am seen around the world as an expert on crime reduction, city development, and in a different part of my life an expert on securities law. I don't mean securities securities, I mean financial securities law."

Giuliani went on to describe coverage of his consulting work as "totally, totally and completely unfair and without any description of what I actually do."

"They make try to make it sound like I'm a world traveling lobbyist and what I am is a world traveling expert of crime reduction, terrorism, economic development and various aspects of international law and American law that is now becoming international law," he said.

Giuliani defended his work for Middle Eastern countries like Qatar, which he said was a staunch ally of the United States at the time and claimed that he never worked for Saudi Arabia, which his former law firm Bracewell and Giuliani represented in Texas court cases. Giuliani left that firm in January.

"I let the State Department know that I was doing it," he said of his work for Qatar. "They were supportive of it. I got paid for services. I did that in the best interests of my country. It was a different Qatar then, that was completely allied with the United States in the war against Iraq."