The smell of smoke was noticeable in central Kiev on Wednesday and Mayor Vitali Klitschko said on Telegram fires had broken out in two districts.
An air raid alert was issued only after the first explosions occurred.
The eastern Ukrainian city of Kharkiv was also attacked overnight with missile strikes in two districts damaging more than 10 houses, Mayor Ihor Terekhov said on Telegram.
Ukraine has been fighting off a Russian invasion for more than four years with support from Western allies.
Ukrainian President Volodymyr Zelenskiy is expected to meet with and US President Donald Trump on the sidelines of the NATO summit in Ankara on Wednesday.
Zelenskiy is seeking increased deliveries of urgently needed Patriot air defence missiles to help counter Russian ballistic missile attacks.
Kyiv has been targeted by Russian ballistic missiles for the third time in a week.
Zelenskiy said on Tuesday Ukraine had signed three more "drone deals" with Denmark, Estonia and the Netherlands, making available its expertise gained from more than four years of war with Russia.
Zelenskiy announced the deals in posts on social media on the sidelines of the NATO summit, saying Kyiv had now clinched nine such accords.
Ukraine has developed a highly sophisticated drone industry after having only limited expertise in the sector when Russia invaded its smaller neighbour in February 2022.
Zelenskiy has travelled widely to promote the deals, particularly in the Middle East, where Gulf countries were obliged this year to counter Iranian strikes.
In announcing the deal with Denmark, Zelenskiy said the agreement "opens up greater opportunities for joint defence production, the exchange of expertise, and transparency in weapons exports".
He said Denmark had been the first country to offer joint production in Ukraine "and it is absolutely fair that Denmark will now have access to Ukrainian exports of weapons tested in war".
In a post on X at the end of the first day of meetings, Zelenskiy said Ukraine "rightfully belongs here" and repeated that Kyiv's main aim at the gathering was to "secure more air defense and stronger diplomatic positions".
Zelenskiy has pointed to Ukraine's need to boost defences against Russian ballistic missiles after two attacks on the Ukrainian capital in the past week. Nineteen people died in Kyiv in the latest assault on Monday.
with dpa
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