Gay rights campaigners were arrested on Friday in Moscow while staging a "kiss-in" protest outside the building of the State Duma, the lower house of parliament, over a proposed bill banning homosexual "propaganda."

A group of 20 mostly young opponents embraced and kissed their same-sex partners to protest against the bill, their third such action there in a week.

The bill could lead to gay men and women being fined for demonstrating or kissing in public, a decision condemned by the United States and rights groups.

The 388-1 vote on Friday in support of the bill, the first of three readings, came hours after the demonstration. Witnesses said officers detained 20 supporters and opponents of the bill as small scuffles broke out.

The bill aims to shield Russians aged up to 18 from what its authors call dangerous ideas on freedoms spread by Western-backed advocates and social media.

'Of course we need this law'

In its current form, the bill 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 could be fined up to 500,000 rubles ($16,500).

It is the latest in a series of restrictive laws passed by parliament since president Vladimir Putin’s return to power in 2012 in the face of widescale protests.

The ruling party’s bill is based on local laws already passed in Putin's native city of Saint Petersburg and five other Russian regions.

Dmitry Sablin, a deputy from the ruling United Russia party, called the law a necessity. "Just look at what is happening in Spain. Just look at what is happening in France! Of course we need this law," he said.

Moscow authorities have broken up several attempts to stage gay rights parades over the past seven years.

Homosexuality became decriminalised in Russia at the end of the Soviet era. But top officials continue to express homophobic views in public, referring to the gay community as "people of a non-traditional sexual orientation."

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 legislatorshave also expressed sympathy with the draft.