Google CEO Sundar Pichai has spoken out about the alleged Russian influence campaign that occurred on its platform last year, admitting that the tech giant has made mistakes.

It emerged in recent months that Russian operatives and trolls – seemingly linked to a state-sponsored move to influence the 2016 presidential vote in the US – purchased advertising on Google products including YouTube, Gmail and the search engine itself.

"We take it very seriously. We are concerned about political interference," he told Spanish newspaper El Pais, in an article published Thursday (7 December).

"What happens on Google is seen all over the world, it appears on the front page of every newspaper," Pichai continued. "Given the scale, scope and impact, we are clear that we have made mistakes.

"But we have also improved. At times like this we can only assume [the mistakes] and improve."

Google, owned by Alphabet Inc, was placed alongside Facebook and Twitter at a US congressional hearing on 1 November, where representatives from each firm were grilled by politicians.

In an earlier statement, Google said it had a "set of strict ads policies including limits on political ad targeting and prohibitions on targeting based on race and religion." It revealed that an internal investigation was underway to "investigate attempts to abuse our systems."

Yet claims of political meddling were only a slice of Google's most recent issues with abuse.

In November, its video hosting platform YouTube was accused of being a breeding ground for paedophile commenters. At the same time, officials admitted that the website had mounting problems with the uploading of exploitative video content featuring children.

The same month, Google went into damage control after YouTube search terms were tampered with to show "profoundly disturbing" results – including "how to have s*x with your kids."

All in all, not an easy year for one of the most powerful technology companies in the world.

But looking forward, Pichai told ElPais that Google will continue to battle unwanted content on its products – from state-sponsored advertising to Islamic State-linked terrorist material.

He said: "As a service for billions of people, we reflect on how much encryption is correct. In addition to addressing the content, we talk with governments, we listen and we seek out how to improve."