Personnel bag samples as they swab railings near a bench covered in a protective tent at The Maltings shopping centre in Salisbury, southern England, on March 16, 2018, as investigations and operations continue in connection with the major incident sparked after a man and a woman were apparently poisoned in a nerve agent attack in Salisbury on March 4.
NATO Secretary General Jens Stoltenberg said March 16, the alliance did not want a return to Cold War hostilities with Russia while expressing support for Britain's strong stance on the nerve agent attack. / AFP PHOTO / Ben STANSALL        (Photo credit should read BEN STANSALL/AFP/Getty Images)
Source: Kremlin likely approved poisioning
British authorities examining the poisoning of former Russian spy Sergei Skripal believe the daring placement of the nerve agent on his door shows a sophistication that likely had the approval of the Kremlin, a source briefed on the investigation has confirmed to CNN.
01:48 - Source: CNN
UK nerve agent poisoning 15 videos
Personnel bag samples as they swab railings near a bench covered in a protective tent at The Maltings shopping centre in Salisbury, southern England, on March 16, 2018, as investigations and operations continue in connection with the major incident sparked after a man and a woman were apparently poisoned in a nerve agent attack in Salisbury on March 4.
NATO Secretary General Jens Stoltenberg said March 16, the alliance did not want a return to Cold War hostilities with Russia while expressing support for Britain's strong stance on the nerve agent attack. / AFP PHOTO / Ben STANSALL        (Photo credit should read BEN STANSALL/AFP/Getty Images)
Source: Kremlin likely approved poisioning
01:48
Now playing
- Source: CNN
Russia's state-owned RT network on Thursday aired an interview with the two men suspected by UK authorities of poisoning former Russian spy Sergei Skripal and his daughter, one day after Russian President Vladimir Putin encouraged the suspects to speak to the media. In an interview with RT editor-in-chief Margarita Simonyan, two men who identified themselves as Alexander Petrov and Ruslan Boshirov said they had nothing to do with the poisoning of the Skripals in Salisbury, England, saying they had reached out to RT to tell their side of the story.
Novichok suspects: We were just tourists
02:11
Now playing
- Source: CNN
Former Russian spy Sergei Skripal and his daughter, Yulia Skripal, at a restaurant in Salisbury, UK.
UK police: Facial tech reveals poison suspects
02:15
Now playing
- Source: CNN
theresa may uk nerve agent poisoning 1
May: Nerve agent poisoning deeply disturbing
00:54
Now playing
- Source: CNN
Trump Putin SPLIT 0316
Trump expels 60 Russian diplomats over UK attack
00:50
Now playing
- Source: CNN
KUWAIT CITY, KUWAIT - DECEMBER 13: Czech soldiers in chemical protection suits take part in a chemical attack response drill conducted at the U.S. Embassy by civil defense authorities and troops from the United States, Germany, and Czech Republic December 13, 2002 in Kuwait City, Kuwait. The exercise, dubbed 'Event Horizon,' was staged to test the coordinated emergency response to a mock attack on the U.S. Embassy in Kuwait by terrorists using deadly sarin nerve gas.
What is Novichok and how does it kill?
01:34
Now playing
- Source: CNN
UK nerve agent attack1
Where and when did nerve agent attack happen?
02:09
Now playing
- Source: CNN
putin response russian spy lon orig bks_00003009.jpg
Reporter confronts Putin about spy poisoning
01:30
Now playing
- Source: CNN
boris karpichkov intv
Fmr. KGB agent told something bad would happen
03:57
Now playing
- Source: CNN
US President Donald Trump (R) and Russia's President Vladimir Putin talk as they make their way to take the "family photo" during the Asia-Pacific Economic Cooperation (APEC) leaders' summit in the central Vietnamese city of Danang on November 11, 2017.
World leaders and senior business figures are gathering in the Vietnamese city of Danang this week for the annual 21-member APEC summit. / AFP PHOTO / POOL / JORGE SILVA        (Photo credit should read JORGE SILVA/AFP/Getty Images)
Russia accuses US of nerve agent attack
01:53
Now playing
- Source: CNN
Russia's track record of poisoning its enemies
Not the first time Russia linked to poisoning
02:56
Now playing
- Source: CNN
Nikki Haley
Haley: Russia responsible for UK poisoning
02:14
Now playing
- Source: CNN
Trump lawn
Trump: We'll condemn Russia if they poisoned ex-spy
00:52
Now playing
- Source: CNN
theresa may parliament 3-12-2018
May: Russia likely behind nerve agent attack
01:01
Now playing
- Source: CNN
SALISBURY, ENGLAND - MARCH 07:  A police tent is seen behind a cordon outside The Maltings shopping centre where a man and a woman were found critically ill on a bench on March 4 and taken to hospital sparking a major incident, on March 7, 2018 in Wiltshire, England. Sergei Skripal, who was granted refuge in the UK following a 'spy swap' between the US and Russia in 2010, and his daughter remain critically ill after being exposed to an 'unknown substance'.  (Photo by Matt Cardy/Getty Images)
Police: Russian spy was deliberately poisoned
02:28
Now playing
- Source: CNN