The owner of the online message board 8chan says he is soon heading to the US.

Jim Watkins lives in the Philippines. US legislators want to question him on his site's use as an outlet for violent white supremacists.

Watkins has not specifically said he will give evidence, but he tweeted portions of an email he said he had sent to House Homeland Security Committee leaders expressing willingness to speak by phone.

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8chan was effectively knocked offline on Monday after two companies cut off vital technical services in response to word that the gunman who killed 22 people in El Paso, Texas, on Saturday posted a racist anti-Latino "manifesto" to the site.

8chan was already well-known for trafficking in anonymous hate speech and incitement of hate crimes.