Kim could be seen smiling as he looked inside the vehicle.
The North Korean leader was quoted as saying the regime could take more goodwill measures if the USA reciprocated with genuine measures to build trust, and that the two countries should take legal and institutional steps to avoid antagonising each other.
The State Department is declining to release any additional information about the calls.
SINGAPORE (Reuters) - U.S. President Donald Trump and North Korean leader Kim Jong Un pledged on Tuesday to work toward complete denuclearization of the Korean peninsula while Washington committed to provide security guarantees for its old enemy.
Many North Korea watchers have noted that the Singapore summit agreement lacks substance, despite Trump touting it as "very comprehensive". The U.S. would also stop joint military exercises in South Korea.
Recover remains of prisoners of war from the 1950-1953 Korean war. But the North has long sought an end to the USA military presence in the South, where Washington has around 28,000 troops stationed to protect it from its neighbour.
Sebastian Gorka praised President Trump after his summit with Kim Jong Un that went "beyond all expectations".
His announcement was a surprise even to President Moon Jae-in's government in Seoul, which worked in recent months to help bring about the Trump-Kim summit.
President Donald Trump's announcement that the U.S. will stop military exercises with South Korea startled Tokyo and Seoul, unsettled United States lawmakers, and took at least some parts of the Pentagon by surprise.
In a press conference on day two in Singapore, Trump told the media that he trusts Kim will begin to dismantle his nuclear weapons program as well as its testing site.
Rishi Kapoor, often in the news for his tweets, as usual had a fun take on the Donald Trump and Kim Jong Un meet in Singapore.
"No one has shown more contempt for other nations and for the well-being of their own people than the depraved regime in North Korea", Trump said at the time. I think he's going to start now.
In response to a question on whether the two leaders will meet again, Trump said: "We'll meet again, we'll meet many times".
Trump said Tuesday that Warmbier "did not die in vain" and "had a lot to do with us being here today".