A volley of Russian missiles wounded dozens of people and damaged a children's hospital Wednesday, the worst attack on Kyiv in months as Ukrainian defenders downed dozens of attack drones targetting the southern city of Odesa.

Ukraine's air force said it had downed all 10 missiles targeting the city and the health ministry said 53 people had been wounded, including two children.

Most injuries were caused by "glass shards, household items and the shock wave" as missile debris fell in eastern and southern parts of the city, the ministry added.

Wednesday's strike, which caused the highest number of wounded in months, was the second in a week.

In another attack overnight Sunday to Monday, eight missiles headed for the capital were shot down.

"The enemy used ballistic weapons," the Kyiv City Military Administration said, adding that Russia was "intensifying the missile terror of Kyiv."

Meanwhile, Ukraine's main mobile operator Kyivstar on Wednesday said its service was being gradually restored after being hit by an unprecedented cyberattack that Kyiv blamed on Russian hackers.

On Tuesday an attack paralyzed the networks of Kyivstar and its 24 million subscribers, with Ukraine's SBU security service contributing to the repairs.

"Our specialists have started to restore telephone calls in all of Ukraine," Kyivstar spokesperson Irina Lelichenko said on Facebook.

The return of services would be "gradual" and problems could remain as teams worked to restore text message and data services, she added.