WATCH: Shocking moment rocket hits an apartment block in Kyiv

This is the shocking moment a rocket hits an apartment block in Kyiv, been captured on CCTV.

Ukrainian officials have urged people in the city to take shelter after Russian troops reached the city and attacked a military base.

Meanwhile, Kyiv officials are warning residents that street fighting is under way against Russian forces as Ukraine’s president refused to leave the city.

The warning issued on Saturday advised residents to remain in shelters, to avoid going near windows or on balconies and to take precautions against being hit by debris or bullets.

Russian troops continued towards Ukraine’s capital early on Saturday as explosions reverberated through the city and the president urged the country to “stand firm” against the siege that could determine its future. He refused American help to leave, saying: “The fight is here.”

Hundreds of casualties were reported in the fighting, which included shelling that sliced through a Kyiv apartment building and pummelled bridges and schools. There also were growing signs that Russia may be seeking to overthrow Ukraine’s government, which US officials have described as Russian President Vladimir Putin’s ultimate objective.

In a statement issued several hours earlier, Ukraine President Volodymyr Zelensky said of Russia: “This is the night they will storm.”

As his country confronted explosions and gunfire, and as the fate of Kyiv hung in the balance, Mr Zelensky appealed for a ceasefire and warned in a bleak statement that multiple cities were under attack.

“This night we have to stand firm,” he said. “The fate of Ukraine is being decided right now.”

Mr Zelensky was urged to leave Kyiv by the US government but turned down the offer, according to a senior American intelligence official, who quoted the president as saying that “the fight is here” and that he needed anti-tank ammunition but “not a ride”.

US defence officials believe the Russian offensive has encountered considerable resistance and is proceeding slower than Moscow had envisioned, though that could change quickly.

The Kremlin accepted Kyiv’s offer to hold talks, but it appeared to be an effort to squeeze concessions out of Ukraine’s embattled leader instead of a gesture towards a diplomatic solution.