The Kremlin said in a statement on Friday that the Russian President Vladimir Putin has signed a new military doctrine, while Ukraine announced suspending passenger and cargo train services to the Black Sea peninsula of Crimea due to security concerns. The new military doctrine says the main external risks for the country are the expansion of NATO's military capabilities and destabilization in several regions, RIA news agency reported. The doctrine also says the main internal risks are activities to destabilize situation in the country and the activities of terrorists, it added. Meanwhile, Ukraine's state rail company Ukrzaliznytsia said on Friday it would suspend passenger and cargo train services to the Black Sea peninsula of Crimea, which was annexed by Russia in March, due to security concerns. Ukrzaliznytsia said cargo trains would be suspended from Friday, while passenger routes would gradually cease running over the weekend and on Monday. It did not say how long the suspensions would be in place or specify what the security concerns were. "In order to ensure the safety of passengers ... (the railway) will cut the route of trains to Crimea off at Novooleksiyvka and Kherson," it said in a statement, referring to two towns on the Ukrainian mainland near Crimea.