NATO Secretary General Jens Stoltenberg stressed today that the "100% security guarantee that an attack on an ally will generate a response from the entire Alliance" does not apply to Kiev , ruling out sending combat troops on the ground to Ukraine if Russia launches an offensive on the country. Ukraine has urged Western countries to be "firm and vigilant" towards Russia, after US President loe Biden kept up pressure on his Russian counterpart, Vladimir Putin, by announcing a small shipment of troops to Eastern Europe.