More Russians regret the breakup of the Soviet Union than at any other time since 2004, an opinion poll shows.

In a survey whose results were published on December 19, two-thirds -- or 66 percent -- of respondents answered "yes" when asked whether they regret the 1991 Soviet collapse.

That is up from 58 percent a year earlier and is the highest proportion since 2004, the last year of President Vladimir Putin's first term, Levada said.

One-quarter of respondents said they do not regret the Soviet breakup, the lowest proportion since 2005, and 9 percent said they could not answer.

Putin, president from 2000-08 and 2012 to the present, has often played up the achievements of the Soviet Union while playing down some of its darkest chapters.

In 2005, Putin called the Soviet breakup the "greatest geopolitical catastrophe" of the 20th century, citing the large numbers of Russians it left outside Russia.

In March, when asked what event in the country's history he would like to have been able to change, he named the collapse of the Soviet Union.

But Levada said that Russians' concerns about their economic security today were among the main reasons for the increase in the number voicing regret.

A highly unpopular plan to raise the retirement age by five years has stoked antigovernment sentiment and pushed Putin's own approval ratings down this year.

The peak of regret over the Soviet collapse came in 2000, when 75 percent of Russian polled by Levada answered "yes" to the same question.

This year, Levada surveyed 1,600 people nationwide in the November 22-28 poll.

The pollster said that 52 percent of respondents named the collapse of the Soviet Union's "single economic system" as the main thing they regretted.

Worries about their current economic situation and prospects were a major factor for many of those respondents, Levada said.

At the same time, 36 percent said they miss the "feeling of belonging to a great power," and 31 percent lamented mistrust and cruelty in society.

With reporting by Vedomosti