Russia's parliament on Wednesday approved legislation that allows elections to be held over three days, in a move the opposition said was aimed at hollowing out democratic polls.
A bill that allows elections to be held over "several but no more than three days" was adopted by parliament's lower house, the State Duma, in a key second reading.
The amendments allow elections to be held outside polling stations and enable voters to cast ballots in various "public spaces," said the State Duma.
The changes came after President Vladimir Putin oversaw a deeply controversial seven-day vote that amended the constitution and allowed him to potentially stay in the Kremlin until 2036.
During the June 25-July 1 plebiscite makeshift polling stations were set up at unlikely locations including buses, tents and street benches.
The voting process, which was not monitored by proper election observers, was ridiculed on social media and criticized by Kremlin critics.
Leading opposition politician Alexei Navalny said the referendum had set "a record in faking votes" and the result had "nothing in common with people's views."
Putin's critics said elections held over several days would be more difficult to monitor and easier to rig.
"They are trying to finish off the institution of elections without realizing that they are digging a grave for themselves," Moscow city councilor Yulia Galyamina said on Facebook, referring to the authorities.
Even the Kremlin-friendly leader of A Just Russia party, Sergei Mironov, criticized the bill.
"From now on people will doubt and ask just how legitimate this or that vote is," the party quoted Mironov as saying.
Parliamentary elections are set to take place next year but some observers say they could actually be held this year.
Regional elections will take place across Russia in September.