Russia's justice ministry has branded Russia's only major private pollster a "foreign agent," a stigma that could lead to its closure.

The ministry issued a statement Monday evening saying that the Levada polling agency has been listed as a "foreign agency" after a snap inspection found some irregularities.

Following major anti-government protests, Russia adopted a law in 2012 that requires all NGOs receiving foreign funding and found to engage in vaguely defined "political activity" to register as "foreign agents." Those who fail to comply face fines and potential closure.

The move comes less than a week after the respected pollster founded by and named after prominent sociologist Yuri Levada published its latest election survey, indicating a drop in the ruling party's ratings. Russia holds a parliamentary election on Sept. 18.