BEIJING (Reuters) -China's export growth slowed in the January-February period largely due to base effects, and though the data beat expectations, Russia's invasion of Ukraine has heightened uncertainty over the outlook for global trade this year.

Outbound shipments rose 16.3% in the first two months of the year from the same period a year earlier, official data showed on Monday, beating analyst expectations for a 15.0% rise, but down from 20.9% gain in December.

Imports increased 15.5%, easing from a 19.5% gain in December and below the forecast 16.5% increase.

The customs agency publishes combined January and February trade data to smooth distortions caused by the Lunar New Year, which can fall in either month.

Factory activity normally slows considerably during the long holiday as workers return to their home towns. But for the third year in a row, many factory workers did not return home because of concerns about COVID-19, which kept some factories operating.

"These numbers will probably be well received. China's exports are high and also the imports are continuing," said Louis Kuijs, Asia Pacific chief economist at S&P Global Ratings, adding that exports remain one component of the economy still supporting growth.

"We need to see how long the economic impact (from the Ukraine crisis) will last. China's economy overall is big and should be to able to continue to grow even in the face of external shocks but export growth will be affected."

China's booming exports outperformed expectations for much of last year and buoyed growth in the world's second-largest economy, but analysts expect shipments to slow eventually as overseas demand for goods eases and high costs pressure exporters.

Russia's invasion of Ukraine late last month, which it calls a "special operation", and mounting international sanctions against Moscow have raised fresh risks for the global economy, adding to months-long strains for China's factories from worldwide supply chain snags.

Tian Yun, former vice director of the Beijing Economic Operation Association, expects China-Europe trade may be disrupted due to the conflict in Ukraine.

"If the Ukraine crisis halts China-EU freight train services or leads to a slower operation efficiency, there will be adverse impact to EU and China's trade. This might be the biggest risk," Tian said.

Chinese exporters with exposure to Ukrainian markets have delayed shipments, while some factories with business in Russia have been waiting for payment from their clients before arranging the next shipments, factory officials and analysts told Reuters.