A defiant Ukrainian President Volodymyr Zelenskyy issued an impassioned plea for help to the world Tuesday, thanking the West for its support and saying his country would not yield to the overwhelming might of the Russian military.

Everyone was anticipating a Russian invasion of Ukraine, and Russian President Vladimir Putin obliged by sending his country’s military into the country in the early hours of February 24th in a large-scale assault by land, sea, and air.

Russia intensified strikes on cities across Ukraine on Tuesday, but the advance of foreign forces ground to a halt outside Kyiv as local troops and volunteers steeled themselves for a fierce battle for the capital.

President Vladimir Putin ignored months of intensifying warnings by President Joe Biden and other western leaders that Moscow would face “swift and severe costs” if Russia invaded Ukraine.

The U.S. has intelligence that Russian commanders have received orders to proceed with an invasion of Ukraine, with commanders on the ground making specific plans for how they would maneuver in their sectors of the battlefield, a U.S. official told CBS News.