Facebook on Tuesday said that the coronavirus outbreak was undercutting sales of the advertising that accounts for nearly all of its revenue, despite the fact that the amount of users who spend time on the social network has been increased.

“We don’t monetize many of the services where we’re seeing increased engagement, and we’ve seen a weakening in our ads business in countries taking aggressive actions to reduce the spread of COVID-19,” the company said in a statement.

The company said messaging across its platforms had increased more than 50% over the last month in many of the worst affected countries. In Italy specifically, users have been spending 70% more time in its apps.

Twitter had also previously reported a boost in active users but the company pulled its first-quarter revenue outlook and forecast an operating loss due to the outbreak.

Many advertisers have pulled marketing budgets to rein in costs because of virus-related uncertainty.

Google and other digital advertising companies are also seeing revenue growth wither as marketers slash spending.

Although millions of people are staying at home and spending more time on social media, video streaming and other online services, the demand for the created ad space is weak, so prices are falling.