Facebook has removed over 100 pages and accounts in the Philippines, including several linked to President Rodrigo Duterte, that it said violated its policies on spam.

The social networking giant said in a statement posted on Monday that it deleted 95 pages and 39 accounts "for violating our spam and authenticity policies".

It said the pages and accounts, which were mostly political or entertainment-themed, directed visitors to "low-quality websites that contain little substantive content and are full of disruptive ads".

One page had about 4.8 million followers. "All were sharing links to the same advertising click farms off Facebook... We don't want this kind of behaviour on Facebook - and we're investing heavily in both people and technology to keep bad content off our services," it said.

Among the pages that were removed were Duterte Media, Duterte sa Pagbabago Bukas (Duterte for Tomorrow's Change), DDS, Duterte Phenomenon and DU30 Trending News.

All professed backing for Mr Duterte, 73. But it could not be ascertained whether the administrators of these pages were actual supporters of the President or were just profiting from his popularity.

Manang Imee, a page managed by supporters of Ilocos Norte Governor Imee Marcos, 62, daughter of the late dictator Ferdinand Marcos, was also removed. She is a close political ally of Mr Duterte.

"This takedown is a small step in the right direction, and we will continue working to find and remove more bad content," said Facebook.

In April, Facebook blocked a number of websites that supported Mr Duterte but which were suspected of spreading fake news.

At least 20 confirmed sites with links from pro-Duterte Facebook pages were blocked, with notices citing security issues.

The websites carried bogus reports designed to help Mr Duterte. One claimed that Chinese President Xi Jinping had promised in a recent speech to defend him for pulling the Philippines out of the International Criminal Court.

Facebook's recent crackdown on spam networks in the Philippines comes five months before the country holds its mid-term elections.

Over 18,000 candidates are seeking national and local seats, in what is seen as a barometer of public support for Mr Duterte.