Facebook's Mark Zuckerberg has admitted that more work is needed to stamp out neo-Nazi hate speech on the world's biggest social networking site.

He met with German Chancellor Angela Merkel's chief of staff in Berlin, to address critics' claims that Facebook needs to respond to anti-immigrant postings more quickly.

Violence against migrants and refugees has spiked in the country, after Ms Merkel announced that Germany's borders were open to Syrians in August.

Hate: Facebook boss Mark Zuckerberg understands that more work is needed to stamp out hate speech on the social media site, after a spike in violent crimes against refugees and migrants in Germany

Response: Mr Zuckerberg met with German Chancellor Angela Merkel's chief of staff in Berlin, to address critics' claims that Facebook needs to respond to anti-immigrant postings more quickly

Facebook has faced months of criticism from politicians and regulators in Germany over its privacy practices and a slow response to anti-immigrant postings by neo-Nazi sympathisers.

‘We in Germany obviously want illegal content to be removed from the internet,’ said chief of staff Peter Altmaier, after a meeting with Mr Zuckerberg in Berlin.

‘That concerns not only Facebook, but Facebook among others.

‘My impression is that Mr Zuckerberg understood the importance of this issue.’

He described the meeting as ‘very good and constructive’.

While Facebook’s rules forbid bullying, harassment and threatening language, critics say it doesn’t enforce them properly.

This comes despite Facebook having hired a Bertelsmann business services unit to monitor and delete racist posts on its platform in Germany.

Problem: German Chancellor Angela Merkel and lawmakers vote on the introduction of expedited asylum proceedings in the German Bundestag in Berlin, Germany, February 25

The Facebook boss attended a technology showcase in the German capital, after Facebook opened a new office there last week.

He posted pictures of himself jogging with a minder at the Bradenburg Gate on his Facebook page.

‘I was able to go for a run this morning,’ he wrote. ‘It’s my first time running in snow in 20 years.’

In September last year, Ms Merkel confronted Mr Zuckerberg in a conversation overheard at the UN.

Speaking to the European leader at a luncheon, Mr Zuckerberg was heard saying 'We need to do some work' in reference to the German effort against racist posts on the internet.

'Are you working on this?' Ms Merkel, who has seen an increase in violence against immigrants in her country during a massive intake of Syrian refugees, pressed.

Mr Zuckerberg replied, 'Yeah', before a speaker at the event in New York made the rest of the conversation inaudible.

On tour: Mr Zuckerberg posted pictures of himself jogging with a minder at the Bradenburg Gate on Facebook

The Facebook boss attended a technology showcase in the German capital, after Facebook opened a new office there last week

Mr Zuckerberg has announced a partnership with European research institutions in artificial intelligence (AI), beginning with the donation of four graphics processing unit (GPU) servers to the Technical University of Berlin.

Facebook is testing a personal digital assistant called 'M' within its messenger service that is powered by AI and can answer questions with live human help and perform tasks such as buying gifts online and booking restaurants.

'It was very clear from the beginning that we couldn't do this without a significant part of that research being done across Europe,' Mr Zuckerberg said of Facebook's AI research.