CHISINAU, May 1 (Reuters) - Authorities in Moldova on Monday detained a leading figure in long-running opposition protests calling for the resignation of the pro-European government as she attempted to leave the country, the anti-corruption prosecutor's office said.

Marina Tauber has spearheaded street protests denouncing President Maia Sandu, who has championed the rapid integration into the European Union of Moldova, an impoverished ex-Soviet state lying between Ukraine and EU member Romania.

Tauber is a senior member of Moldova's second largest opposition party led by Ilan Sor, who lives in exile in Israel and was sentenced last month to 15 years in prison in connection with a bank fraud.

Sandu and other officials say Tauber's role in the often noisy protests are part of attempts to disrupt public affairs in Moldova and act in the interests of Russia.

"Every person is obliged to abide by the legal norms of the Republic of Moldova and any action in violation of these norms is subject to punishment ... by law," presidential press secretary Irina Gotisan said in a statement.

Tauber faces fraud charges over party financing and was arrested while attempting to leave for Israel in violation of court orders. She remained in custody on Monday evening, according to the prosecutor's office.

Moldova has denounced Russia's invasion of Ukraine and accuse the Kremlin of attempting to destabilizes the country.

Sandu won election in 2020 by a landslide and her PAS party, which upholds her pro-European policies, holds a majority in parliament. The protests have posed little threat to her authority.

Tauber is also expected to play a role in an election being held in the Moldovan region of Gagauzia, which is populated mainly by ethnic Turks who adhere to the Orthodox Church and favour close ties with Russia.

All eight candidates for the post of "bashkan" were pro-Russian. Tauber was expected to campaign on behalf of one of the two hopefuls who will contest a run-off later this month.

Sandu and her PAS party have been criticized for failing to field a candidate on that grounds that any such hopeful would suffer a crushing defeat in the region.

Another Moldovan region, Transdniestria, broke away from Moldova in the 1990s and is propped up by 1,500 Russian "peacekeepers" in place since a brief war in the aftermath of the Soviet collapse.