Pro-Isis twitter accounts have been 'celebrating' the Chattanooga shooting of US Marines in Tennessee, US, on Thursday, that left four Marines dead.
However, there has been no official claim by the Islamic State of the Chattanooga shooting.
The shooter has been identified as 24-year-old Mohammod Youssef Abdulazeez, who, investigators have said, appeared to have acted alone, though any possible links or association are being investigated.
While Thursday's shooting is so far being seen as an act of 'domestic terrorism', authorities are reportedly also investigating if the shooter had any links to Isis.
Some Isis-affiliate Twitter accounts have reportedly put up posts claiming the attack, though there has been no official claim by the terror group.
The Islamic State had first claimed an attack on US soil when two gunmen attempted to carry out an attack at a Prophet Drawing contest in Texas in May this year. They were shot down by security forces before they injured anyone.
Authorities are still investigating the motive of Abdulazeez, 24, a Kuwaiti-born Jordanian who opened fire at two military sites in Chattanooga on Thursday, killing four US Marines, and injuring three other people, before he himself died. It is still not clear if he was shot by the police or whether he killed himself.
What has further raised suspicion of an Isis link to the Chattanooga shooting is the flurry of Twitter activity by Isis supporters, who reportedly posted images and expressed adoration for the shooter, according to a tweet by Rita Katz, head of SITE Intel Group, which monitors online activities of jihadists.
— Rita Katz (@Rita_Katz) July 16, 2015
Following May's Texas attack, Isis had warned of further attacks in the US, claiming that it had '71 soldiers in 15 American states'.
One of the Texas gunmen, Elton Simpson, had pledged allegiance to Isis chief Abu Bakr al-Baghdadi on twitter before the attack.