TBILISI (Reuters) - Georgia's ruling party on Friday accused the United States of pursuing a policy of "threats and blackmail" against Georgia over its decision to impose visa restrictions against members of parliament who back a bill on "foreign agents".

The draft law has sparked a political crisis in the South Caucasus country. Protesters have taken to the streets in some of the biggest rallies since Georgia gained independence from the Soviet Union to voice opposition to the bill, which has been condemned by domestic critics, the U.S. and the EU as authoritarian and Russian-inspired.

U.S. Secretary of State Anthony Blinken said on Thursday that the U.S. was imposing new visa restrictions on Georgia and launching a review of bilateral cooperation between the countries over the bill, which would require organisations receiving more than 20% of their funding from abroad to register as "foreign agents".

Blinken, announcing the actions in a statement, said the law would "stifle the exercise of freedoms of association and expression" and impede independent media organizations' work.

In a statement posted to Facebook, the ruling Georgian Dream party called Washington's move "nothing but a gross attempt to restrict Georgia's independence and sovereignty" and said it was deeply damaging to the countries' partnership.

The head of the Georgian Dream governing bloc's parliamentary faction called the U.S. ban "comical" and said it threatened to restrict Georgia's independence.

"The country's independence is not for sale for any visas", Mamuka Mdinaradze wrote on Facebook.

The bill has cleared Georgian parliament but was vetoed by the president last week.

Georgian Dream has vowed to move forward with the bill and said on Friday it would begin the procedure to override the veto next week.

(Reporting by Reuters; Writing by Lucy Papachristou; Editing by Andrew Osborn and Toby Chopra)