(Reuters) -Russian air defences shot down four Ukrainian drones headed for Moscow on Saturday, the city's mayor said, while one of the capital's main airports temporarily halted outgoing flights. Mayor Sergei Sobyanin said emergency services were working at the sites of the downed drones, but gave no information on potential damage.

Ukraine said Saturday it struck an airbase in Russia, which continued overnight to use hundreds of drones in its stepped-up bombing campaign. The fresh wave of attacks signal a breakthrough isn't expected anytime soon in efforts to end the more than three-year-old war.

Russia's largest airports experienced hours-long flight delays and cancellations on July 5, as authorities imposed temporary restrictions due to a reported threat of Ukrainian drone attacks, the pro-Kremlin Telegram channel Shot reported.