Speaking with reporters on his way to Saudi Arabia on Tuesday, Mattis said the missile, which the Pentagon said blew up shortly after launch on Saturday, was not an intercontinental ballistic missile, meaning it could not reach USA territory.
The aim of the five-nation tour, Pentagon officials said in announcing the trip, is to reaffirm key US military alliances, engage with strategic partners in the Middle East and Africa, and discuss cooperative efforts to counter destabilizing activities and defeat extremist terror organizations.
U.S. President Donald Trump has taken a hard line with North Korean leader Kim Jong Un, who has rebuffed admonitions from China and proceeded with nuclear and missile programmes seen by Washington and others as a direct threat.
North Korea still has many technical problems to resolve, but the intensity of its current testing worries Pentagon strategists.
North Korea has warned of nuclear war if provoked.
Russian officials later said that the deconfliction channel had been suspended, but US troops adopted a more defensive posture to guard against misunderstandings.
Pence also warned that recent U.S. strikes in Syria and Afghanistan showed that the Trump administration's resolve should not be tested.
Until Mattis spoke Tuesday, the Pentagon and CJTF had been tight-lipped on whether the US was finding ways to work around the channel suspension.
"We continue to deconflict with the Russians for safety of flight to avoid any kind of misunderstanding or any kind of inadvertent running into each other, frankly, in the air, as we both work against targets in the same vicinity", Mattis said.
Asked about the ongoing humanitarian crisis in Yemen, Mattis said the United States was in favor of a swift political solution.
Mattis is expected to broach the subject with King Salman of Saudi Arabia, a country he described as "a pillar of our security framework for the region and for American interests".
Discussing the deconfliction channel "was not a productive thing to do", Dorrian said, "and that's the reason that we are no longer doing readouts of what those discussions are, and we will not get back into that business".
The U.S.is conducting counterterrorism operations and airstrikes against al-Qaeda militants in Yemen (al-Qaeda in the Arabian Peninsula), while a small number of U.S forces are assisting the Saudi-led coalition fighting Iran-backed Houthis with limited intelligence and refueling support.