A conservative ally of German Chancellor Angela Merkel warned Russia on Tuesday against failing to cooperate with the probe into a nerve agent attack on a former Russian double agent in Britain. "The behavior of the British government is rational," Norbert Roettgen, chairman of Germanys parliamentary foreign affairs committee, told Reuters. "The discovery of a Russian military substance means that Russia cannot refuse cooperation in the clearing up of this matter," he said. "If Russia does not cooperate, there must be a joint Western response." Sergei Skripal, 66, and his daughter Yulia have been in hospital since March 4 when they were found unconscious in the English city of Salisbury. British Prime Minister Theresa May said on Monday it was highly likely Moscow was to blame after Britain identified the substance as part of a group of nerve agents developed by the Soviet military in the 1970s and 1980s. She gave the Kremlin until the end of Tuesday to disclose details of the Novichok nerve agents program to the Organization for the Prohibition of Chemical Weapons. "It was an indiscriminate and reckless act against the United Kingdom, putting the lives of innocent civilians at risk. And we will not tolerate such a brazen attempt to murder innocent civilians on our soil," May added. Asked about possible sanctions against Russia, Roettgen said any measures should target the fudged boundary between the Russian state, security apparatus and organized crime. "This case should be reason for Britain to examine its open stance towards Russian capital of dubious origin," he said. Putin spokesman Dmitry Peskov told reporters that Skripal worked for British intelligence and was poisoned on British soil, and therefore the incident "has nothing to do with Russia, let alone the Russian leadership." Peskov also said the Kremlin hasnt heard any official statements of Russian involvement. Skripal was a Russian military intelligence officer when he was recruited to spy for Britain in the 1990s. He was jailed in Russia in 2006 for revealing state secrets before being freed in a spy swap in 2010. He had settled in the cathedral city of Salisbury, 90 miles (140 kilometers) southwest of London. He and his daughter were found comatose on a bench near the city center after visiting an Italian restaurant and a pub. US Secretary of State Rex Tillerson cast Skripal’s poisoning as part of a "certain unleashing of activity" by Russia that the United States is struggling to understand. He warned that the poisoning would "certainly trigger a response." Tillerson, echoing the British governments finger-pointing toward Moscow, said he did not yet know whether Russias government knew of the attack, but that one way or another, "it came from Russia." He said it was "almost beyond comprehension" why a state actor would deploy such a dangerous substance in a public place in a foreign country where others could be exposed. "I cannot understand why anyone would take such an action. But this is a substance that is known to us and does not exist widely," Tillerson told reporters as he flew from Nigeria to Washington. "It is only in the hands of a very, very limited number of parties."