After ultimatum deadline passes, UK leader readies response

Investigators in protective suits work at the scene near the Maltings shopping centre in Salisbury, England, Tuesday, March 13, 2018. The use of Russi

Investigators in protective suits work at the scene near the Maltings shopping centre in Salisbury, England, Tuesday, March 13, 2018. The use of Russi

Investigators in protective suits work at the scene in the Maltings shopping centre in Salisbury, England, Tuesday, March 13, 2018. The use of Russian

Investigators in protective suits work at the scene in the Maltings shopping centre in Salisbury, England, Tuesday, March 13, 2018. The use of Russian

Russian Foreign Minister Sergey Lavrov smiles during a meeting with South Korean head of National Security Chung Eui-yong at the Russian foreign minis

Russian Foreign Minister Sergey Lavrov smiles during a meeting with South Korean head of National Security Chung Eui-yong at the Russian foreign minis

LONDON (AP) — Britain's prime minister is set to chair a meeting of the national security council Wednesday to consider sanctions against Russia after Moscow ignored a deadline to explain how a nerve agent developed by the Soviet Union was used to target a former spy in England.

Theresa May is weighing a range of economic and diplomatic measures against Russia Wednesday in response to the assault on Sergei and Yulia Skripal. The father and daughter remain in critical condition in a Salisbury hospital

Moscow says it won't comply with Britain's demands unless the government provides samples of the poison collected by investigators. Russia's embassy in the U.K. warned Tuesday that any sanctions would "meet with a response."