Though he denied the Russian state had been involved in hacking, Putin said individual "patriotic" hackers could mount their own attacks.
Russian state gas exporter Gazprom, which supplies around a third of the EU's gas, is keen for Nord Stream 2 to be built by 2019.
Feyenoord's painful wait for a first Dutch league title since 1999 has come to an end on Sunday when a home-victory in Rotterdam against Heracles Almelo made them champions of the Netherlands.
The final result was decided by a 50/50 combination of jury and public votes.
All countries qualified for the Eurovision Song Contest's Grand Final, which is scheduled for May 13, have become known after the second semi-final on May 11.