Russian air defence units downed six Ukrainian drones headed for Moscow on Sunday, mayor Sergei Sobyanin said.

Ukraine said it struck a Russian air base on Saturday, while Russia continued to attack Ukraine with hundreds of drones overnight as part of a stepped-up bombing campaign that has dashed hopes for a breakthrough in efforts to end the more than 3-year-old war.

Ukraine has concluded deals with European partners and a US defence company to step up the production of drones, President Volodymyr Zelensky said on Saturday. Zelensky said Kiev has "reached an agreement with one of the leading American companies to significantly increase our joint efforts" on drones,