MOSCOW (Reuters) - A masked man broke into the home of the head of Russia’s Central Election Commission on Friday and repeatedly tried to taser her, the Interior Ministry said, two days before an election that has triggered street protests.

Russian investigators said they would look into whether the attack was connected to her work. The commission head, Ella Pamfilova, said she suspected robbery was the motive.

Pamfilova and her colleagues, citing a technicality, refused to register several opposition candidates for the Moscow city election, leading to the biggest sustained protest movement in Russia since 2011-2013.

“The masked intruder broke in through a window and got onto the house’s terrace and repeatedly tasered the home owner (Pamfilova) and then fled,” the Interior Ministry said in a statement. The house is situated outside Moscow.

An unnamed law enforcement source told the Interfax news agency that the taser device appeared not to have worked and the intruder had struck Pamfilova several times.

Pamfilova, who took part in a conference in Moscow on Friday, appeared on state television looking shaken up.

She said she had hurt her finger and scratched her side while grappling with her assailant and then resisting him with a chair.

She said the intruder was lanky and appeared to be young and that she believed the most likely motive for the intrusion was an attempted robbery.

Prominent opposition figure Alexei Navalny said on social media he thought the authorities had invented the attack on Pamfilova to distract attention from what he said was groundwork for electoral fraud in Moscow and other places where elections to local legislatures will be held.

Pamfilova, 65, has been a focus for protesters’ anger after barring opposition candidates from Sunday’s election for Moscow’s parliament. She said they had not collected enough genuine signatures to take part, which the excluded candidates said was a fabrication designed to stop them winning seats.

The Moscow vote is seen as a dry run for a national parliamentary election in 2021 with allies of Navalny seeing it as a chance to make political inroads in the capital.

Navalny has called on his supporters to vote tactically to try to reduce the chances of the ruling United Russia party - which supports President Vladimir Putin - winning.

PRO-PUTIN PARTY AT LOW EBB

The elections present a challenge for the authorities with the popularity of United Russia at its lowest in more than a decade, according to official pollsters.

In Moscow, all of its candidates are running as independents, a tactic widely seen as aiming to prevent them from being damaged by the party’s waning support.

The party has served as a lightning rod for public anger over a government move last year to hike the retirement age, a deeply unpopular reform that compounded growing dismay over five years of falling real incomes.

The party’s approval rating stood at 32.6% last month, just shy of its lowest level in more than 13 years of polling data, according to state pollster VTsIOM.

Police detained over 2,000 people at this summer’s protests in Moscow, which began in mid-July, with courts jailing some of those who took part for up to four years. The Kremlin has shrugged off the protests’ significance.

At well over 60 percent, Putin’s personal approval rating is still high compared with many other world leaders, but is lower than it used to be.

Last year the 66-year-old former KGB intelligence officer won a landslide re-election and a new six-year term that runs until 2024.