MOSCOW, January 13 (RIA Novosti) – Thousands of Russian activists gathered in the center of Moscow on Sunday to hold a protest march against a law banning US nationals from adopting Russian children.

Co-chairmen of the People’s Freedom Party (Parnas) Boris Nemtsov, Mikhail Kasyanov and Vladimir Ryzhkov arrived at the site of the opposition gathering in Strastnoy Boulevard to lead one of the protest march’s columns.

The other column on the other side of the boulevard will be led by Left Front coordinator Sergei Udaltsov.

The Moscow authorities Moscow City Hall gave permission for a march with the participation of up to 20,000 people. The march will follow the same route as two of last year’s protests against the rule of President Vladimir Putin. But opposition leaders stressed that Sunday’s rally was a separate event.

The ban is part of a wider response by Moscow to the Magnitsky Act, a US law that imposes travel bans and other sanctions on Russian officials suspected of human rights abuses. The law was signed into force by US President Barack Obama late last year.

The Russian law, which was fast-tracked through parliament and signed by Putin late last year, has been largely supported by the general public here, with 56 percent of respondents in favor of the ban in a poll carried out in December by the Public Opinion Foundation (FOM).

State Duma lawmakers said the law was a response to what they called the inaction of US officials over the deaths of 19 Russian children adopted by Americans since 1999. Over 45,000 Russian children have been adopted by US families in that period, according to the US State Department.

But the adoption ban proposal has drawn a furious reaction from human rights groups and a number of people were detained in Moscow in late December as they protested against the bill outside parliament.