Twitter said it has closed an Iran-based network of accounts fanning the flames around racial justice protests in the US sparked by the death of George Floyd.

Floyd's death on May 25 became a symbol of what many say is systemic racism and abuse of African Americans by police, and has sparked months of often violent protests across the US.

The network of more than 100 accounts "artificially amplified" conversations on topics including Floyd's death, Black Lives Matter and social justice issues, the platform said in a statement Thursday.

Twitter also said it had closed more than 900 accounts linked to the Thai army for attacking prominent opposition figures and diffusing pro-government and military propaganda. The kingdom is seeing a groundswell of pro-democracy protests demanding the government step down and the monarchy reform.

Many of the banned Thai accounts tried to deflect blame from the military for the Korat shooting -- a gun rampage earlier this year in which a soldier killed 30 and injured 57 people at a shopping mall. "Some of them are still in a Cold War mindset, but they don't know that in the digital world you leave technology footprints that can be traced," Thai opposition MP Wiroj Lakkhanaadisorn told AFP.

Army spokesman Lieutenant General Santipong Thampiya denied the suspended Twitter accounts were linked to the military, dismissing the investigation as unfair and lacking in-depth analysis.

In a statement, Thursday Facebook also said it had closed accounts in multiple countries, from government or military-linked networks it said were spreading disinformation.

In Myanmar -- which heads to the polls next month -- Facebook said it had removed 17 pages, 50 accounts and six Instagram accounts.

Many of these were critical of civilian leader Aung San Suu Kyi and her party, as well as a "small number" targeting the long-persecuted Rohingya Muslim community.

"Our investigation found links to members of the Myanmar military," said Facebook, which is scrambling to improve its image in a nation where online hate speech is thought to have spilled into offline violence.

The platform said it had also removed more than 850 dubious accounts spanning Nigeria, Azerbaijan, the US, Kenya and Botswana in the first week of October alone.

Last month it closed 511 accounts, mainly based in Russia, China and the Philippines.