A new opinion poll indicates that 48 percent of voters would cast their ballots for incumbent President Vladimir Putin if Russia's presidential election were held in the near future.

The figure in the April 21-24 poll by the independent Levada-Center was down from 62 percent in a similar poll in April 2015 and 53 percent in January 2016.

Putin, in power as president or prime minister since 1999, is widely expected to seek a new six-year presidential term in a March 2018 election. He has not announced his candidacy.

Levada polled 1,600 adults nationwide, asking them whether they would vote -- and for whom -- if the election were held "next Sunday." The pollsters did not name any candidates, leaving it up to the respondents to do so.

Flamboyant ultranationalist Vladimir Zhirinovsky and Communist Party leader Gennady Zyuganov received 3 percent piece, while opposition politician Aleksei Navalny was one of four people who were each named by about 1 percent of respondents.

Staunch Putin critic Navalny is campaigning for the presidency, but it is unclear whether the authorities will put him on the ballot.

Putin was named by 49 percent of respondents to a similar Levada poll in April 2014, and by 29 percent in April 2013.

In Russian presidential elections, a candidate must win more than 50 percent of the votes cast to avoid a runoff.

According to official results, Putin won about 64 percent in 2012, about 72 percent in 2004, and about 53 percent in 2000.

In a March 31-April 3 Levada poll, 64 percent of the respondents said they would like Putin to win another term in 2018, while 22 percent said they would like to see another person as president, and 14 percent were unable to answer the question.