Presidential candidate Pete Buttigieg has responded to President Donald Trump's comment earlier this week about being 'absolutely fine' with the mayor's gay marriage.

'Even though they're paying lip service to the idea of - like the president was asked about my marriage, so he could have the opportunity to say he's fine with it,' Buttigieg said.

'That's nice,' he added sarcastically.

Buttigieg was speaking on Friday evening while on the campaign trail in Des Moines, Iowa at a discussion about his book, Shortest Way Home, which he released earlier this year.

But it was his comments on the Trump administration's record on LGBT rights that sparked the most interest.

Buttigieg was speaking on Friday evening, pictured, while on the campaign trail in Des Moines, Iowa at a discussion about his book, Shortest Way Home, which he released earlier this year

President Donald Trump told Fox News in an interview that he thinks it's 'great' openly gay presidential candidate South Bend, Indiana Mayor Pete Buttigieg can appear on stage with his husband and it be 'normal'

Trump tells Fox News Channel's 'The Next Revolution with Steve Hilton' in an interview airing Sunday that 'I think it's absolutely fine' that Buttigieg and his husband, Chasten, are open about their relationship on the campaign trail.

Buttigieg, the mayor of South Bend, Indiana, has been married to Chasten since June 2018.

The two appeared on stage together at the Human Rights Campaign's 14th annual Gala in Las Vegas last weekend, where they shared a kiss in front of the audience after Buttigieg delivered the event's keynote speech.

Trump agreed with Hilton that Buttigieg's candidacy is a sign of progress for the country.

He says, 'I think it's absolutely fine, I do,' Trump responded. 'I think it's great. I think that's something that perhaps some people will have a problem with; I have no problem with it whatsoever. I think it's good.'

Another sneak peek of our EXCLUSIVE interview with @realDonaldTrump - listen below to what he has to say about @PeteButtigieg, and don't miss the full interview this Sunday at 9PM ET on @FoxNews! pic.twitter.com/YS9kobn4d0 — The Next Revolution (@NextRevFNC) May 16, 2019

Buttigieg (right) appeared with his husband, Chasten (left), at the Human Rights Campaign Gala last weekend. The two kissed on stage after the candidate delivered a keynote address

Despite President Trump's words, Buttigieg attacked the current administration's policies on gay and transgender Americans.

A story in the The Daily Beast reported how the adopted children of LGBT parents are considered being born out of wedlock, even if they biologically related. The U.S. citizenship of the parents no longer grants the child the same citizenship.

'We find out this week that they changed the State Department guidance, so if you are, for example, in an international adoption scenario, and you're a same-sex couple, as far as the United States government is concerned, you have a child born out of wedlock. Think about what that means. It means you are not a citizen of the same country as your own child at the time that they are born. And that's discrimination,' Buttigieg said.

Trump claims to be a friend to gay Americans, and tweeted during his own presidential campaign in July 2016: 'Thank you to the LGBT community! I will fight for you while Hillary brings in more people that will threaten your freedoms and beliefs.'

Democratic presidential candidate Pete Buttigieg, right, and husband Chasten Glezman Buttigieg wave to the crowd during at the Human Rights Campaign Gala dinner last Saturday

Buttigieg is the first openly gay candidate to run in the Democratic primaries

During his campaign, Trump even suggested he'd appoint conservative justices to overturn a Supreme Court decision legalizing same-sex marriage. But he called the issue 'settled' shortly after his election.

But such claims don't wash with Butigieg. 'Every policy turn we've seen out of this administration has been hostile to LGBTQ people,' he said.

Buttigieg sparred with Vice President Mike Pence in April. Pence's stances on LGBTQ issues have faced criticism from gay rights activists.

Pence signed the Religious Freedom Restoration Act while he was governor of Indiana. Critics of the law contend that individuals and businesses could use it to discriminate against the gay community on the basis of religion.

Pence also signaled support for federal funds to be allocated for gay 'conversion therapy' on his 2000 US House campaign website, where it said, 'Resources should be directed toward those institutions which provide assistance to those seeking to change their sexual behavior.'

Buttigieg, who came out as gay in 2015 and married Chasten in June 2018, was also critical of Trump's transgender military policy.

The president announced during a tweet in 2017 that transgender individuals would not be allowed to serve in the U.S. military.

Two years later, in April, the policy that disallows people from serving in the military unless they adhere to the sex they are assigned at birth was implemented.

'Needless to say, the war on trans Americans, the attack on the ability of transgender Americans to serve in the military, is an example of that hostility toward LGBTQ people,' Buttigieg said.

Buttigieg will continue on his two-day trip in Iowa on Saturday with events in Iowa City and Dubuque.

Buttigieg has embraced the rigors of the presidential campaign trail, taking questions from reporters at nearly every stop.

A former long-shot candidate, the calm, understated Indianan swiftly rose in the ranks among the crowded field of Democratic contenders, and averages 6.8 per cent support among Democratic primary voters.

The field grew to 24 candidates on Thursday when New York City Mayor Bill de Blasio announced he would also vie for the party's nomination in 2020.

Buttigieg dispelled ideas that his campaign was 'peaking early.'

'It's not like we're in first place,' he told reporters on Thursday, adding that he is 'thrilled with the fact that we are obviously running ahead of a lot of better-known competitors and got a lot of favorable attention.'

But the presidential sweepstakes 'is a long run,' he said. 'This is a marathon. We've got a long way to go. We are frankly ahead of where I hoped to be. But now we are right where I want to be.'