President Volodymyr Zelensky has told Ukrainians they have "withstood the blow" of Russia's invasion as he urged citizens to continue fighting. In an impassioned speech delivered from Kyiv on Saturday night, Mr Zelensky told the country that the time has come for them to launch a fightback. "You need to go out and drive this evil out of our cities," he said. The rallying cry came alongside a plea to US President Joe Biden to source more combat jets for Ukraine. US officials are believed to be in discussions with political leaders in Poland over the possibility of Warsaw providing Ukraine with a number of MiG fighter jets. Poland has been slowly phasing the Soviet-era fighter out of use - and officials are understood to be weighing whether to provide them to Ukraine, where pilots are not trained to fly Western-made jets. Some reports suggest they could be exchanged for new US-sponsored replacements. The Russian invasion of Ukraine has entered its 11th day, with some experts suggesting the invasion may have stalled in places - despite President Vladimir Putin's insistence on Saturday that the operation is "going to plan." While fighting has continued in many parts of the country, Moscow's forces have only captured one major Ukrainian city, Kherson - though it has made other key advances, such as seizing the Zaporizhzhia nuclear power plant on Friday.