MOSCOW — Russia will close the American consulate in St. Petersburg and kick out diplomats in response to Monday’s coordinated expulsion of Russian diplomats from the United States and a number of European countries, Foreign Minister Sergei Lavrov said Thursday.

The move continues an ongoing escalation of tit-for-tat between Moscow and the West that began in early March with the alleged poisoning of a former Russian double agent on British soil with an Soviet-designed nerve agent.

Lavrov said that U.S. Ambassador Jon Huntsman has been asked to appear at the Foreign Ministry – “where my deputy minister Sergei Ryabkov will lay out for him the content of these retaliatory measures against the United States,” he said.

Lavrov did not specify the number of U.S. diplomats to be expelled, but said it would be “a similar amount” and includes the closure of the U.S. consulate in St. Petersburg. The U.S. operates other consulates in Yekaterinburg and Vladivostok, they were untouched.

The Russian who was attacked, Sergei Skripal, remains in critical condition in a British hospital. But health officials said his daughter, Yulia Skripal, who was also exposed to the nerve agent, has responded well to treatment and is no longer in critical condition, The Associated Press reported.

Medical director Dr. Christine Blanshard says “she has responded well to treatment but continues to receive expert clinical care 24 hours a day.”