(Reuters) - Russia is investigating whether a North Korean intercontinental ballistic missile crashed in its waters during a test launch on Wednesday, state media quoted Deputy Foreign Minister Andrei Rudenko as saying.

RIA and TASS news agencies quoted Rudenko as saying that Russia's defence ministry was investigating, but "so far we have no clear information that the missile fell in Russia's economic zone".

The Hwasong-18 missile is the core of North Korea's nuclear strike force and the test-fire was a "strong practical warning" to the United States and other adversaries, the country's state media said in reporting the launch.

The test was condemned by the United States, South Korea and Japan, but Russia's Rudenko said it was a reaction to actions by Washington and its allies which "actually provoke North Korea to build up its defence power".

North Korea has been under United Nations sanctions for its missile and nuclear programmes since 2006 but the U.N. Security Council has been divided for the past several years on how to deal with it. Russia and China, which both wield veto powers on the council, have said more sanctions will not help and want such measures to be eased.

U.N. Assistant Secretary-General Khaled Khiari said on Thursday that the latest North Korean missile flight lasted about 74 minutes and travelled over 1,000 km (625 miles). Khiari said it crashed into the sea within Russia's exclusive economic zone but close to Japanese waters.

(Reporting by Reuters; editing by David Evans)