Britains security minister called on Russia to give details about the Novichok nerve agent attack on a former double agent and his daughter after two British citizens were poisoned with the same substance as British police scrambled to determine how the couple were exposed to the agent. The two Britons are critically ill after what is thought to be a chance encounter with the poison Novichok in the village of Amesbury after the March attack on former Russian agent Sergei Skripal and his daughter Yulia in nearby city of Salisbury in March. Britain has accused Russia of the poisoning of the Skripals, a charge Russia has repeatedly denied. "The Russian state could put this wrong right, they could tell us what happened, what they did and fill in some of the significant gaps that we are trying to pursue," Security Minister Ben Wallace told BBC radio on Thursday. "They (Russia) are the ones who could fill in all the clues to keep people safe." "The possibility that these two investigations might be linked is clearly a line of inquiry for us," said Neil Basu, head of Britains counter-terrorism police force. Police announced late Wednesday that tests on the couple, named locally as 44-year-old woman Dawn Sturgess and 45-year-old man Charlie Rowley, revealed they had been exposed to Novichok, but could not say whether it was the same batch used on the Skripals. Novichok is a military-grade nerve agent developed by the Soviet Union during the Cold War. Vladimir Shamanov, head of the Russian parliaments defense committee, said Britain should ask Russian experts to help investigate the new poisoning case. He was cited by the RIA news agency on Thursday. The Russian embassy in the Netherlands also said on Twitter that Britain was "dumb" to use Novichok story again in the middle of soccer world cup being held in Russia.