Pictured: Washington couple Jay Austin and Lauren Geoghegan, who were killed in a terror attack in Tajikistan on Sunday

The two Americans killed in a terror attack in Tajikistan have been identified as avid bicyclers Jay Austin and Lauren Geoghegan.

The Washington DC couple, who decided last year to leave their jobs and travel around the globe on bikes instead, were remembered as warm-hearted, adventurous and 'larger than life'.

On Sunday, they and two other cyclists were killed when a driver allegedly rammed his car into them and joined his passengers in going after the cyclists with knives.

A Daewoo sedan plowed into a group of seven foreign bicyclists about 60 miles south of the Tajik capital, Dushanbe, on Sunday, according to local police.

The people in the vehicle then 'exited the car and stabbed the cyclists with knives,' the U.S. Embassy in Tajikistan said in a statement Monday.

One of the other two people killed was 56-year-old Amsterdam man René Wokke, whose girlfriend Kim Postma, 58, is seriously injured in the hospital.

Local reports claim Wokke was an experienced cyclist who had taken his bike through 130 countries, and that the couple had chosen Tajikistan as they felt some neighboring countries were too dangerous.

Swiss couple Markus Hummel, 62, and Marie-Claire Diemand​, 59, were also cycling with the group when they were ambushed .

Hummel was killed in the attack, while Diemand was hospitalized with injuries.

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Jay Austin, 29, had worked at the Department of Housing and Urban Development for seven years and his girlfriend at Georgetown University before the couple took off in July 2017 on their trip of a lifetime

Tajik officials say one half of the couple is from Sweden and the other from the Netherlands.

Another cyclist with the group, a French citizen, escaped without injury and had been questioned by police. A woman from Switzerland was also injured.

Lauren's aunt shared her grief with Facebook friends on Monday, and encouraged them to visit the couple's website to best honor their memories.

'On Sunday my beautiful and beloved niece Lauren Geoghegan, 29, and her amazing boyfriend, Jay Austin, were tragically killed while adventure cycling in Tajikistan,' she wrote.

'They were the target of a horrific terrorist attack.

'There are no words. Our family is shocked and devastated by this senseless loss.

'Lauren and Jay chronicled their journey and experiences with fabulous photographs and captivating blogs. In tribute to them, I invite you to visit their website so that we can remember them for the dream they were outrageously living out and not the way they died.

'Thanks for your prayers at this time. We need them.'

Austin and Geoghegan were remembered friends as kind and happy, while family mourned the beloved and gentle couple

A fellow bicyclist who had met the couple on their trip and only parted ways with them a few days before they were killed said she and her cycling group would 'forever be inspired by their kindness and open mindedness and their happiness for the good and simple things'.

Geoghegan and Austin hauntingly predicted their biggest risk would come from humans in cars - but they had not prepared for the shock attack that took their lives and two others

Jay's mother, Jeanne Santovasco, told The Washington Post her son was: 'just a gentle soul, who cared about the world, not leaving any footprint and leaving it a better place'.

Austin had worked at the Department of Housing and Urban Development for seven years before he took off on his bike ride in July 2017.

Geoghegan worked as a senior admissions officer at Georgetown University before she agreed to join her boyfriend on the trip of a lifetime.

Hauntingly, their blog had addressed the idea they could be killed on their trip.

In a Q&A segment, the couple noted: 'Relatively speaking, bike touring is really safe'.

'Despite what the news would have you believe, the world is a really wonderful, caring place, and stories of kidnapped travelers or mauled cyclists are the rare exception, not the norm.'

The attack took place in the district of Danghara in Tajikistan, 90 miles south of the capital Dushanbe

One of the other two people killed was 56-year-old Amsterdam man René Wokke (pictured), whose girlfriend Kim Postma, 58, is seriously injured in the hospital

While Austin and Geoghegan admitted they could be harmed, they said they were prepared for dangerous diseases and angry wildlife - and were hoping no human would stand in the way of their dream trip, especially a human in a car.

'The greatest danger to us—any of us, really—are humans in cars, who kill more people than anything else in the world,' they wrote.

'We keep an eye on news reports, monitor trends, and choose routes that minimize risk, but don't avoid it altogether (as, obviously, that's impossible).

'Life is almost always boring and uneventful in almost all places, and so we're not ruling out entire nations simply because something once happened there or because our government and that country's government don't get along so well.'

Security forces killed four suspected attackers on Monday and detained one.

Safarov Zafarjon Jumayevich, 19, is one of four suspects detained in the alleged attack

One of those originally on the wanted list and then reported killed included Asomiddin Madzhidov (pictured)

Among the dead suspects was 21-year-old Jafariddin Yusufov, the owner of the Daewoo Leganza car that struck the tourists on Sunday afternoon, local officials said.

Jafariddin Yusufov, a suspect in the case and the owner of the Daewoo Leganza that struck the tourists, was killed

'(The suspects) had knives and firearms,' said interior minister Ramazon Hamro Rahimzoda, adding that two other cyclists, Swiss and Dutch nationals, were injured and hospitalised.

'One tourist received a knife wound and is being given medical assistance. The victim's condition is stable,' said Rahimzoda, without mentioning a nationality.

Islamic State released a video on Tuesday purportedly showing attackers pledging allegiance to the militant group before killing four Western tourists in a knife and car-ramming attack in Tajikistan.

The terror group sought to bolster its claim of responsibility for an attack which killed four Western tourists including two Americans on Sunday.

In a statement, ISIS said that a 'detachment from the soldiers of the Caliphate' had carried out the attack against 'citizens of Crusader coalition countries,' according to intelligence monitor SITE.

Islamic State released a video on Tuesday purportedly showing attackers pledging allegiance to the militant group before killing four Western tourists in Tajikistan

On Tuesday, an ISIS outlet published a video of five men pledging allegiance to its leader Abu Bakr al-Baghdadi.

The men, who speak Russian, sit under a black Islamic State flag and refer to each other by Arab names.

Some of them appear similar to the suspects whose photographs have been published by Tajikistan's interior ministry.

But the Tajik government has accused a banned Islamist opposition party of being behind the attack.

The Islamic Renaissance Party of Tajikistan (IRPT) party's exiled leaders denied any link to the attack and said the authorities were using the incident for political purposes.