Russian President Vladimir Putin signed a law on Friday to limit the number of local staff working at foreign diplomatic missions and other agencies and ordered the government to draw up a list of "unfriendly" states that will be subject to the restrictions.

The new law, published on the Kremlin website on Friday, authorizes the government to restrict or even ban employment contracts with "state bodies and state institutions of foreign states committing unfriendly acts against the Russian Federation."

The restrictions come into effect from the day the decree was published.

The bill comes amid an escalating diplomatic row between Russia and the Czech Republic that led both sides to expel diplomats, with several other European countries following suit. 

The Czech announced to expel 18 staff members from the Russian embassy in Prague on April 18. One day after, Moscow expelled 20 Czech diplomats in retaliation. 

On Thursday, Prague announced to cut back on diplomats from Moscow, and Kremlin responded with similar action, demanding the Czech embassy in Moscow to reduce its number of employees.

Relations between the two countries have plunged to their lowest level since the Cold War. The Czechs accused Moscow last week of a role in explosions at an arms depot in 2014, which Russia denies.

The European Union expressed its full support and solidarity with the Czech Republic, the EU Commission said late on Monday.

"The European Union is deeply concerned about the repeating negative pattern of dangerous malign behaviour by Russia in Europe," the Commission said in a statement.

Read more: What is going on between Czechia and Russia?

(With input from agencies)