Russia's parliament has given initial backing to a bill banning homosexual "propaganda" among children that could lead to gays being fined for demonstrating or kissing in public, a move condemned by the United States and rights groups.
The 388-1 vote in the first of three readings Friday came hours after police detained more than 20 mostly young opponents who were staging a "kiss-in" protest outside the building of the State Duma lower house.
The nationwide proposal is the latest in a rapid sequence of restrictive legislation voted through by parliament since President Vladimir Putin returned to power last year in the face of widescale protests.
The ruling party bill is based on local laws already passed in Putin's native city of Saint Petersburg and five other Russian regions, and aims to shield Russians aged up to 18 from what its authors view as dangerous ideas on freedoms spread by Western-backed advocates and social media.
"Just look at what is happening in Spain. Just look at what is happening in France! Of course we need this law," said ruling United Russia deputy Dmitry Sablin.
In Washington, State Department spokeswoman Victoria Nuland said: "We are deeply concerned by this draft legislation in Russia that severely restricts freedom of expression and assembly for lesbian, gay, bisexual and transgender individuals and, indeed, for all Russians."
London-based group Amnesty International also condemned the proposed law, with David Diaz-Jogeix, deputy director of the Europe and Central Asia programme, saying: "This law is an attack on the right to freedom of expression.
"There is no legal definition in the Russian law of what constitutes ?propaganda of homosexuality' and the law could be interpreted very loosely.
"They are going to punish people for something which is perfectly legitimate -- expressing themselves, being themselves."
Outside the Duma Friday, a group of opponents embraced and kissed their same-sex partners in defiance of the bill's proposals, their third such action there in a week. Once again, police moved in to break up the protest.
Witnesses said officers detained 20 supporters and opponents of the bill as small scuffles broke out.
Homosexuality was only decriminalised in Russia after the end of the Soviet era and top officials continue to express homophobic views in public.
Russia's leaders repeatedly refer to gays in official language as "people of a non-traditional sexual orientation".
The Moscow authorities have broken up attempts to stage gay rights parades over the past seven years.
And a 2010 survey by the Levada Centre found that 74 percent of respondents thought homosexuality was either "immoral" or "mentally deficient".
The bill in its current form prohibits "the propaganda of homosexual behaviour among minors" and sets out fines for violations of up to 5,000 rubles ($165) for individuals and up to 50,000 rubles for officials.
Legal entities such as businesses or schools would be fined up to 500,000 rubles ($16,500).
The introduction of a local law in Saint Petersburg last year led to a boycott of the former imperial capital by international gay rights groups while US pop star Madonna handed out pink ribbons at a concert in the city.
The authorities have issued a series of fines against couples who appeared in public kissing or holding hands.
United Russia has enough votes in the lower house to pass any piece of legislation on its own without consulting the other parties. But Communists and other lawmakers have also expressed sympathy with the draft.
Russian state television said members of Russia's gay and lesbian community would be invited to attend the key second hearing that is likely to be held within the next few weeks.
Draft laws move from the Duma to the upper house for a single reading before reaching Putin's desk.