Orlando nightclub shooting: Picture of post-9/11 terrorism transformed

Rachel Henry, Selene Arciga, Nicolette Gullickson, Joanna Lamstein join members and supporters of the LGBT as they gather for a candlelight vigil in front of the White House in Washington. Photo / AP

In the grim statistics of terrorism in America, the shooting at a gay nightclub in Orlando appears to represent the deadliest attack on US soil since September 11, 2001. It may also mark the doubling of the number of people killed in the US by a terrorist motivated by Islamist ideology in the years since September 2001.

Before the attack in Orlando on Sunday, 45 people in the US had died in jihadist terrorist attacks since 9/11 according to a database maintained by the New America, a Washington thinktank. The thinktank has added 50 more deaths to its database due to the attacks in Orlando, taking the toll to 95.

The shooter's ties to terrorism are not yet fully established. Omar Mateen, 29, reportedly called 911 and pledged allegiance to Isis (Islamic State). The group has also claimed credit, though it is not confirmed whether it did in fact have any role.

The New America database on deaths due to terrorism in the US gathers information about violent extremist activity and separates incidents into several groups - including those motivated by jihadist ideology, like al-Qaeda, and those driven by non-jihadist ideologies, like right-wing and left-wing beliefs.

In recent years, domestic terrorism motivated by right-wing hate groups had been behind most deaths. But that changed with the massacre in San Bernardino, California, last December.

The shootings in Orlando would alter the picture further, according to the New America. The data showed that before Sunday, 48 deaths had been linked to incidents of right-wing terrorism. It's possible, however, the attack in Orlando could represent both a hate crime against gay Americans - like those committed by right-wing extremists in other cases - as well as a terrorist attack motivated by jihadist ideology. It's unknown the degree to which the shooter deliberately targeted gay people for slaughter.

New America's figures can change fairly quickly, since the total number of deaths due to terrorism in the US is small, and each attack can involve a large number of fatalities. Before the shooting in San Bernardino, right-wing extremists had killed nearly twice as many people in the US as Islamist extremists had - 48 to 26. The 14 deaths in the San Bernardino shootings, which New America ultimately classified as jihadist terrorism, transformed that tally.

Several Republicans, including Donald Trump, referred to Sunday's shooting as an incident of "radical Islamic terrorism". Democrats, meanwhile, initially described the incident as a hate crime against the LGBT community and denounced loose restrictions on the kind of assault-style rifle used in the attack.

Either way, authorities were quick to condemn the act as terrorism.