He added the US will make efforts to work with the UN, South Korea, China and Japan to find a way out of the situation. Even without its missiles, North Korea has amassed artillery units along its border with South Korea and any military action from Pyongyang could be devastating.
Marine Corps Gen. Joe Dunford, the Chairman of the Joint Chiefs of Staff, said the Coalition's effort had "reduced ISIS-held territory, limited their freedom of movement, destroyed a great deal of their leadership, reduced the flow of foreign fighters into and from the region, diminished their financial resources".
Regarding the North's latest test of what USA officials say was a KN-17 missile, Mattis acknowledged that Pyongyang had likely learned a great deal from the missile which was believed to have survived reentry to some degree.
Kim In Ryong told a news conference that if the Trump administration wants peace on the Korean Peninsula, it should replace the Armistice Agreement that ended the 1950-53 Korean War with a peace accord and halt its anti-North Korea policy, "the root cause of all problems". "We speak routinely when we need to, to work through the deconfliction".
North Korea has made no secret of its desire to develop missiles capable of targeting some of its neighbors and intercontinental ballistic missiles capable of delivering a nuclear warhead to the US mainland. "It wasn't pointed in that direction". Despite tough talk from top United States officials in recent weeks and the deployment of an aircraft carrier strike group to the region, Mr Mattis said, the best option for North Korea is finding an worldwide solution to effectively apply pressure on Pyongyang. "For North Korea to compare what they have been doing to threaten and intimidate their neighbors, as well as the United States, to our routine military exercises - advertised well in advance with full transparency - would be an unfair comparison".
"We're going to continue to work the issue ..."
"There is no escape for ISIS, even while we do all that is humanly possible to shepherd the innocent out of harm's way", he said.
"Whatever the reason for the US strike was, it was illegitimate and marked another flagrant violation of Syria's sovereignty", Russian Foreign Minister Sergey Lavrov said in Cyprus.
In Iraq, U.S. and coalition forces provide equipment and intelligence to Iraqi security forces, the chairman said.
A separate US -backed group of Syrian rebels would push up from the south to block IS escape routes, the USA officials said. When exactly this definition was reclassified was not immediately clear.
East Mosul - which was held by ISIS until past year - is returning to normal, with businesses reopening and kids back in school, Mattis said. "Or - or - you know, apparently against the advice of the Russians".
Russian Federation reportedly made attempts to reach the pro-Assad forces on the ground, but were unsuccessful, the defense official said.