Jeremy Corbyn is not yet prepared to blame Russia for the Sergei Skripal poisoning.

The Labour leader believes British intelligence officials could be wrong, according to his spokesperson.

Corbyn believes the attack could have been carried out by another eastern European state or the mafia.

Theresa May said she was "surprised and shocked" by the comments.

LONDON — Jeremy Corbyn believes there is not enough evidence to conclude that Russia was culpable for the poisoning of Sergei Skripal and his daughter.

Prime Minister Theresa May told the House of Commons today that Vladimir Putin's Russia was responsible for the attack in Salisbury last week and will be subject to a series of punitive measures.

However, shortly after May's speech, a spokesperson for Corbyn told publications including Business Insider that the Labour leader did not believe there was sufficient proof to conclude that Russia carried out the poisoning, suggesting that British intelligence services could be wrong.

"There is a history between weapons of mass destruction and intelligence which is problematic, to put it mildly," they said.

Asked why Corbyn did not explicitly condemn Russia in his response to the prime minister's Commons speech, they added: "Clearly whoever carried out the attack is responsible for what was a completely heinous and reckless act."

The spokesperson also suggested the poisoning might have been a carried out by a "mafia" or another former Soviet state, rather than orchestrated by the Kremlin.

"The break up of the Soviet state led to all sorts of material ending up in random hands," they said.

Prime Minister May said she was "surprised and shocked" by the Labour leader's statement and said most Labour MPs will be "equally surprised" by the spokesperson's comments.

A host of Labour MPs gave their full support to May's speech and suggested their leader should have been stronger in his condemnation of Russia.

Yvette Cooper said Russia "must be met with unequivocal condemnation" while Liz Kendall, John Woodcock and other Labour MPs echoed the prime minister's remarks.

Their Labour colleague Gavin Shuker MP tweeted:

Asked whether Corbyn was concerned by comments made by some of Labour MPs, his spokesperson said: "In these kinds of cases, there are often initial reactions which aren't later backed up by reality or facts."

Skripal and his daughter, Yulia, are in critical condition after being exposed to a military-grade nerve agent in Salisbury, south England last week.