U.S. stock futures pointed to a mixed start for Wall Street on Friday, Sept. 15, after North Korea fired another missile over Japan and police in London declared a terrorist incident had taken place on a busy commuter train at the height of the city's morning rush hour.

European and Asian markets also were mixed following the missile launch from North Korea that came just days after the United Nations agreed to tougher sanctions on Pyongyang.

U.S. Secretary of State Rex Tillerson said that "continued provocations only deepen North Korea's diplomatic and economic isolation," and urged tougher sanctions on the rogue nation. The U.N. Security Council is expected to meet later Friday to discuss the situation.

In London, stocks fell sharply after the London Metropolitan Police issued a statement that said there were a number of "people who have suffered injuries" in the train incident.

"It is too early to confirm the cause of the fire, which will be subject to the investigation that is now underway by the Met's Counter Terrorism Command. The station remains cordoned off and we are advising people to avoid the area," officials said in a statement.

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