U.K. lab unable to identify 'precise source' of Novichok that poisoned former spy

U.K. scientistshave confirmed the nerve agent used to poison a former Russian spy and his daughter was from the Novichok series, but have not verified its "precise source," the head of the lab studying the substance said Tuesday.

Gary Aitkenhead, chief executive of Britain's Porton Down defence laboratory, said his team set out to identify the agent, but "it's not our job to say where that was actually manufactured.

"We were able to identify it as Novichok, to identify thatit was military-grade nerve agent," Aitkenheadtold Sky News.

• U.K. names Novichok nerve agents in ex-spy poisoning: What are they?

"We have not identified the precise source, but we haveprovided the scientific info to government, who have then used anumber of other sources to piece together the conclusions youhave come to," he said.

Britain has saidSergei Skripal and his daughter,Yulia,were poisoned with a Soviet-developed nerve agentand that the Russian state must be behind the attack.

Russia has denied responsibility and suggested the poison may have come from Britain.

President Vladimir Putin said Moscow wantsa thorough probe into the poisoning of an ex-Russian spy in Britain and will demand to be part of it.

He said the type of the nerve agent used in the March 4 poisoning could be made in some 20 nations.

Putin saidgiven the lack of precise information about the agent's origin, "the speed at which the anti-Russian campaign has been launched causes bewilderment."

Putin's spokesman Dmitry Peskov told reporters that Britain will have to apologize to Russia for its "mad accusations" that "have no foundation whatsoever."

Earlier in the day, RussianDeputy Foreign Minister Alexander Grushko, in comments relayed by Russian news agencies on Tuesday, called the poisonings a "provocation arranged by Britain" in order to justify high military spending because "they need a major enemy."

A spokeswoman for the ministry saidBritain's failure to track down the source of a nerve agent shows that the accusations against Russia have been based merely on baseless suspicion.

In a mocking statement posted Tuesday on Facebook, MariaZakharovasaid: "I wouldn't be surprised if tomorrow [British Prime Minister]Theresa May and her bright team say that all their speeches in Parliament and efforts to build a global coalition resulted from the Russian hackers hacking into Disney cartoon studios."

Aitkenhead said on Tuesdaythe attack with thehighly toxic Novichok nerve agent was "probably only within the capabilities of a state actor" because of the "extremely sophisticated methods" required to produce it.

He saidthere is "no way" the nerve agent could have come from the high-security Porton Down facility near Salisbury, where the Skripals were foundpoisoned on March 4.

The global chemical weapons control body will hold an emergency meeting to discuss the poisoning of former spy Skripal, at Russia's request.

OPCW meeting Wednesday

Yury Filatov, Russia's ambassador to Ireland, on Tuesday saidMoscow asked the Organization for the Prohibition of Chemical Weapons "to call an extraordinary session" at its headquarters in The Hague.The organization says the meeting will be held on Wednesday.

FilatovsaidRussia wants Britain to "provide every possible element of evidence" it holds about the poisoning.

He said if the U.K. does not show evidence, "there are ample grounds to assume that we are dealing with a grand-scale provocation organized in London aimed to discredit Russia."