Russian President Vladimir Putin has signed a law on Russian citizenship.

The Russian leader urged unflagging attention to such important tasks as support for prosecution in courts, protection of the environment, and monitoring of the observance of the rights of convicts.

"Germany will keep a cool head and continue weighing in all the decisions in the future," German Chancellor noted, referring to the issue of tanks supplies to Kiev

The Russian missile, capable of carrying nuclear warheads and evading radar, was tested in April amid heightened tensions.