Thousands of UK political ads went missing from Facebook Inc’s (FB.O) searchable advertising database on Tuesday, hampering researchers’ ability to track ads two days before Britain’s general election.

Axar.az reports citing Reuters that Facebook’s ad library, which it launched in the UK in 2018, is a public tool for users to view political advertising on the platform.

The problem affected ads from the ruling Conservative Party, the Brexit Party, and the Liberal Democrats. It was not immediately clear if any Labour Party ads were affected.

“We have fixed the bug and all of the impacted ads in the UK are now back in the ads library,” Facebook said in a statement.

A spokesman also confirmed that some ads in the United States were affected, but declined to answer questions on the scale of the issue there.