The United Kingdom's military has been deployed to assist in the country's ongoing investigation into the poisoning of an ex-Russian spy and his daughter in Salisbury last weekend.

A statement from the U.K.'s defense secretary, Gavin Williamson, obtained by BuzzFeed News stated that the military would assist in the investigation into the nerve agent used to poison Sergei Skripal and his daughter Yulia, who both remain in the hospital. The two were found alive but in critical condition on a park bench on Sunday.

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The sophisticated nature of the assassination attempt has led to speculation that the Russian government may have been behind the poisoning.

"We have the right people with the right skills to assist with this crucial inquiry," Williamson said.

"The military has the expertise and capability to respond to a range of contingencies," added a statement from the Metropolitan Police. "The Ministry of Defence regularly assists the emergency services and local authorities in the UK. Military assistance will continue as necessary during this investigation."

The specific purpose of the military's deployment is unknown, but the statement from Metropolitan Police added that the army would "remove a number of vehicles and objects from the scene in Salisbury town centre."

That statement came after the official number of people possibly exposed to the nerve agent used in the assassination attempt climbed to 21.

Assistant Police Commissioner Mark Rowley implored the public for help uncovering the attackers behind last weekend's poisoning in a Wednesday press conference.

"Did you see anything out of the ordinary? It may be that at the time, nothing appeared out of place or untoward but with what you now know, you remember something that might be of significance," Rowley said.

"Your memory of that afternoon and your movements alone could help us with missing pieces of the investigation. The weather was poor that day so there were not as many people out and about. Every statement we can take is important."