The United States has said Russia should not be acting like a victim after it announced the expulsion of more than 150 diplomats from countries around the world.

The Russian move is a tit-for-tat response to the wave of Western expulsions of Russian diplomats over the poisoning of former spy Sergei Skripal and his daughter, Yulia, in the UK.

It came as a hospital treating the Skripals said the woman was improving rapidly and was now in stable condition, though her father remained in critical condition.

The pair were found unconscious and critically ill in Salisbury on March 4. British authorities blamed Russia for poisoning them with a military-grade nerve agent, accusations Russia has vehemently denied.

Two dozen countries, including the US, many EU nations and Nato, have ordered more than 150 Russian diplomats out this week in a show of solidarity with Britain — a massive action unseen even at the height of the Cold War.

READ MORE: Russian former spy’s daughter ‘conscious and talking’ after poisoning

Russian foreign minister Sergey Lavrov said at a news conference that Moscow will expel the same number of diplomats from each of those countries in retaliation.

Russian Foreign Minister Sergey Lavrov (AP Photo/Alexander Zemlianichenko)Russian Foreign Minister Sergey Lavrov (AP Photo/Alexander Zemlianichenko)

US ambassador Jon Huntsman was summoned to the Foreign Ministry while Mr Lavrov was speaking, where he was handed notice that Russia is responding quid pro quo to the US decision to order 60 Russian diplomats out.

In a statement, Mr Huntsman said there was “no justification” for the move and that it shows Moscow is not interested in dialogue with the United States about important matters.

“Russia should not be acting like a victim,” US State Department spokeswoman Heather Nauert said.

Mr Lavrov also said Moscow will retaliate for the US decision to shut the Russian consulate in Seattle by closing the US consulate in St Petersburg.

READ MORE: Russian former spy’s daughter ‘conscious and talking’ after poisoning

The Foreign Ministry said the US diplomats, including 58 from the embassy in Moscow and two from the consulate in Yekaterinburg, must leave Russia by April 5. It added that the US must leave the consulate in St Petersburg no later than Saturday.

The US consulate in St Petersburg (Dmitri Lovetsky/AP)The US consulate in St Petersburg (Dmitri Lovetsky/AP)

The ministry warned that if the US takes further “hostile actions” against Russian missions, Russia will respond in kind.

“We invite the US authorities who are encouraging a slanderous campaign against our country to come back to their senses and stop thoughtless actions to destroy bilateral relations,” it said.

Mr Lavrov emphasised that the expulsions followed “brutal pressure” from the US and Britain, which forced their allies to “follow the anti-Russian course”.

READ MORE: Russian former spy’s daughter ‘conscious and talking’ after poisoning

He also noted that the job of the international chemical weapons watchdog is to determine what chemical agent was used to poison Mr Skripal and his daughter, not verify the British conclusions.

Mr Lavrov said that Moscow called a meeting on Monday of the secretariat of the Organisation for the Prohibition of Chemical Weapons to discuss the case.

Meanwhile, Salisbury NHS Trust, which oversees the hospital where the Skripals are being treated, said that 33-year-old Yulia is “improving rapidly and is no longer in a critical condition. Her condition is now stable.”

“She has responded well to treatment but continues to receive expert clinical care 24 hours a day,” said Dr Christine Blanshard, medical director at Salisbury District Hospital.

Mr Skripal, 66, remains in critical condition, the hospital said.