Russian President Vladimir Putin has submitted to parliament a number of new constitutional changes, including amendments that mention "God" and stipulate that marriage is a "union of a man and woman."

Putin in January unleashed a political storm by proposing an overhaul of the constitution, the first changes to the basic law since 1993.

Last month, the Russian parliament's lower house unanimously approved the constitutional reform bill in a first reading after less than two hours of debate.

Ahead of a second and key reading set for next week, Putin submitted 24 pages worth of amendments, said State Duma Speaker Vyacheslav Volodin.

"The president's amendments are the result of his dialogue with representatives of all factions (and) civil society," he said in comments released by the State Duma.

The amendments enshrine the mention of Russians' "faith in God" and also stipulate that marriage is a heterosexual union, Deputy Speaker Pyotr Tolstoy told AFP.

Putin said last month Russia would not legalize gay marriage as long as he was in the Kremlin. He said he would not let the traditional notion of a mother and father be subverted by what he called "parent number 1" and "parent number 2."

Under Russian law, only heterosexual couples can adopt children in Russia.

Most Russians identify as Orthodox Christians but Russia is officially a secular state.

The new amendments also ban giving away Russian territory and any call promoting such a move would also be outlawed.

The second reading of the constitutional reform bill is expected to take place on March 10, said a spokeswoman for Pavel Krasheninnikov, co-chief of the constitutional working group.

The spokeswoman told AFP that the text of the amendments was expected to be published later this week.

A public vote on the constitutional reforms has been set for April 22.

(With input from AFP, Reuters)