ISLAMIC State have “trained soldiers” in 15 states across America waiting to carry out deadly missions, according to an online warning from the group. The online warning claimed there were 71 trained soldiers operating on American soil.
The group claimed responsibility for an attack on an event in Texas at the weekend where cartoons of the Prophet Mohammed were on display.
Two gunmen were shot dead during the firefight, in what was IS’s first attack on US soil.
I have homegrown violent extremist investigations in every single state
The threatening post, which could not be independently verified, was seen by US broadcaster Fox News after it appeared on a file-sharing network.
It has been signed by Abu Ibrahim Al Ameriki – a name already known to authorities.
He is thought to have joined a terrorist group in Pakistan several years ago and experts believe the US-based jihadi has also appeared in IS propaganda videos in the past.
“Out of the 71 trained soldiers 23 have signed up for missions like Sunday, we are increasing in number," read the warning.
"Of the 15 states, 5 we will name… Virginia, Maryland, Illinois, California, and Michigan.”
The Texas attack on a ‘Draw the Prophet’ contest on Sunday was thwarted when police shot dead both gunmen.
Referring to the attack, the post added: "The disbelievers who shot our brothers think that you killed someone untrained, nay, they gave you their bodies in plain view because we were watching.”
FBI director James Comey revealed in February that the US police agency was investigating IS links in all fifty US states, describing the terror group’s network as a “chaotic spider web”.
“Until a few weeks ago there was 49 states. Alaska had none which I couldn't quite figure out.
"But Alaska has now joined the group so we have investigations of people in various stages of radicalising in all 50 states.”
The worsening situation comes as US authorities offered a $20million (£13m) bounty on four IS leaders.
The American government is targeting Abd al Rahman Mustafa al Qaduli, Abu Mohammed al Adnani, Tarkhan Tayumurazovich Batirashvili, and Tariq Bin al Tahar Bin al Falih al Awni al Harzin - described as "key leaders" in the terror network.