Russian President Vladimir Putin has submitted to parliament a number of 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.
Shortly afterward, the 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 new proposals, 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, said Deputy Speaker Pyotr Tolstoy.
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.
A member of a Kremlin-appointed constitutional working group, actor Vladimir Mashkov, has suggested that such an amendment would ensure that Russia keeps Crimea — which it annexed from Ukraine in 2014 — or the Kuril Islands — disputed with Japan for decades — even after Putin quits power.
Tolstoy said he was pleased with the draft legislation.
"I believe that most of the proposals that have been discussed have been taken into account," he told AFP.
The 67-year-old Putin, who has dominated Russia for 20 years, has sought to cast himself as a defender of traditional values and rally support by promoting anti-Western and conservative ideas.
Putin's fourth stint in the Kremlin has seen a strong pivot to more conservative policies, with groups promoting fundamentalist Orthodox Christian views gaining more legitimacy and liberal viewpoints attacked as Moscow's relations with the West have soured.
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.
Analysts see Putin's plan to change the constitution as beginning preparations for succession when his current Kremlin term ends in 2024.
At the weekend more than 22,000 people rallied in central Moscow to call on Putin not to stay in power indefinitely.