LONDON (Reuters) - A court in St Petersburg dropped charges against an antiwar priest who was arrested in February after he tried to organise a memorial service for Kremlin critic Alexei Navalny.

The city's court system said on Telegram it had abandoned the case against Grigory Mikhnov-Vaitenko because the statute of limitations on the charges had expired.

An Apostolic Orthodox Church bishop, Mikhnov-Vaitenko was detained near his home on Feb. 17, the day after Navalny died in an Arctic penal colony.

The 56-year-old was charged with attempting to organise a mass rally in a public space, which can risk 15 days in jail or a fine.

Writing on Facebook, his wife thanked his supporters and lawyer. "The prosecution has ten days to appeal. We are home," Natalia Sivohina wrote.

A longtime critic of Russia's war in Ukraine, Mikhnov-Vaitenko joined hundreds of others who were arrested for seeking to mourn Navalny, whose death at the age of 47 sent shockwaves through Russian opposition circles.

Thousands of people braved arrest and turned out at his funeral in Moscow in March to pay their respects, clutching flowers and chanting "We won't forgive."

His widow, Yulia Navalnaya, and supporters have charged that President Vladimir Putin ordered him killed, something the Kremlin fiercely denies.

Mikhnov-Vaitenko served as a priest in the Russian Orthodox Church for years until he was excommunicated for condemning Russia's invasion of Ukraine in 2014.

He then joined the Apostolic Orthodox Church, founded in the early 2000's by other dissident priests who had run afoul of the ROC, which has close ties to the Kremlin.

Shortly after his arrest, the St Petersburg Metropolitanate released a statement denying any links to Mikhnov-Vaitenko and urging its flock to ignore his appeals.

In April, an Orthodox priest who led a prayer service at Navalny's graveside in Moscow was suspended from his clerical duties and ordered to serve three years of "penance."

(Reporting and writing by Lucy Papachristou; Editing by Bill Berkrot)