The eurozone's annual economic growth slowed to 2.2% in the second quarter from 2.5% in the first quarter, according to a second flash estimate from Eurostat.

The seasonally adjusted annual GDP growth rate was revised higher from a flash estimate of 2.1%. Quarter-over-quarter GDP growth was also revised up to 0.4% from the previous estimate of 0.3%.

Data released earlier showed Germany's GDP grew more than expected in the second quarter due to strong domestic demand.

"The upward revision to eurozone GDP growth in [the second quarter] will make policymakers at the [European Central Bank] more confident that they are right to be winding down their asset purchases," Capital Economics senior European economist Jack Allen said.

The region's economic growth is expected to slow only gradually over the next few years, Allen said, adding that GDP growth is expected to be 2.2% in 2018, 2.0% in 2019 and 1.7% in 2020.

Eurostat will release its next estimate for second-quarter GDP growth Sept. 7.