(Reuters) - Russia's foreign ministry said on Thursday that giving Ukraine air defence systems, as requested by Ukraine's president in the U.S. Congress a day earlier, would be a destabilising factor that would not bring peace to the country.

       Ukrainian President Volodymyr Zelenskiy urged American lawmakers on Wednesday to do more to protect his country from Russia's invasion, pushing for the imposition of a no-fly zone and asking for aircraft and defensive systems.

       "Such deliveries ... would be a destabilising factor which will definitely not bring peace to Ukraine," foreign ministry spokeswoman Maria Zakharova told a news briefing.

       "In the long term, they could have much more dangerous consequences," she added.

       The United States and its allies want to avoid NATO being drawn into the Ukraine conflict, but they have supplied Kyiv with military aid since Russia invaded Ukraine on Feb. 24.

       Moscow calls its offensive in Ukraine a "special operation" to destroy its southern neighbour's military capabilities and capture what it regards as dangerous nationalists.

       Slovakia's Prime Minister Eduard Heger on Sunday said NATO could discuss sending his country's Soviet-made S-300 air defence system to Ukraine.

       (Reporting by Reuters; Editing by Frank Jack Daniel)