U.S. President Donald Trump doubled down on his support for North Korean leader Kim Jong Un's scathing view of former U.S. Vice President Joe Biden on Monday, dismissing criticism that he was siding with a dictator over a fellow American.

"Well Kim Jong Un made a statement that Joe Biden is a low IQ individual. He probably is, based on his record. I think I agree with him on that," Trump told a news conference in Tokyo.

The comments reinforced a tweet that Trump sent on Saturday with a similar message. The fact that Trump doubled down in attacking Biden while on foreign soil stirred additional criticism as commentators slammed the president for taking a domestic political spat overseas.

Conservative commentator Bill Kristol wrote on Twitter, "Trump attacking Democrats in Japan reminds me of when VP Quayle took a bipartisan delegation on AF2 to Duarte's funeral in 1990. I still remember Ted Kennedy, before we landed, reminding his colleagues we were representing the U.S. and should leave political disagreements behind."

While writer Steven Beschloss compared it to the 2003 controversy when the country group the Dixie Chicks criticized then-President Bush while performing in the U.K. and the subsequent blacklisting of their music by certain radio stations.

"Do you remember the attacks the Dixie Chicks faced when they complained from London they were embarrassed by George Bush? Will that same crowd condemn Trump for his shameful coveting of a murderous dictator and his support while in Japan of Kim’s attacks on former VP Biden?" Asked Beschloss.

North Korea's state-run news agency issued a stinging attack last week on Biden, who has been critical of the isolated state.

Trump has targeted Biden with increasing criticism as the former vice president rises in polls for the Democratic presidential nomination to challenge Trump in 2020.

The president often derides his political opponents, but his tweet on Sunday and his comments on Monday were notable for the fact that he issued them while abroad and aligned himself with Kim, considered a brutal dictator by many.

Trump has sought to build a strong relationship with the North Korean leader in the hopes of reaching an eventual peace deal.

Trump also knocked Biden and former President Barack Obama on Monday for their efforts to prevent Iran from getting a nuclear weapon. Trump pulled the United States out of a nuclear deal Iran sealed with Washington and other foreign powers.

"Joe Biden was a disaster, his administration with President Obama, they were basically a disaster when it came to so many things, whether it was economy, whether it was military ... no matter what it was, they had a lot of problems," Trump said when asked about criticism that he was favoring Kim over the former vice president.

"So, I'm not a fan."

A commentary by North Korea's KCNA state media on Tuesday slammed Biden for "rhetoric slandering the supreme leadership of the DPRK (Democratic People's Republic of Korea)."