Google has taken down two Chrome extensions, "Add to Feedly" and "Tweet This Page," after users complained that the features gave them invasive advertisements.

Both extensions saw ratings drop from five stars to one before they were removed from the Google store, The Wall Street Journal reported.

They had been "silently updated" to include code for ads that put malware and intrusive ads on users' computers, violating Google's terms of use, according to The Guardian.

The tools, which had fewer than 100,000 users each, started out as legitimate Google extensions, but the codes were reportedly changed after their independent developers were offered money by ad companies.

"It was a four-figure offer for something that had taken an hour to create and I agreed to the deal," wrote Amit Agarwal, developer of Add to Feedly, which had around 30,000 users.

According to The Guardian, Agarwal said he regretted the decision to sell the extension and felt that he had let down its users.

After being contacted by WSJ, Google removed the two extensions.

Tweet This Page was the other extension invaded by ads as first reported by Ars Technica.

Google's web store has thousands of available extensions, many of which have been downloaded millions of times. Add to Feedly and Tweet This Page may not be the only extensions to be infiltrated with malware.

Because Chrome is automatically updated by Google, users should be especially careful when choosing extensions, Ars Technica noted.

"This means that it's up to the user to decide if the owner of an extension is trustworthy or not, since you are basically giving them permission to push new code out to your browser whenever they feel like it," the outlet said.

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