UPDATE 1-Russia jails Kremlin critic Navalny for 10 days

(Updates with detail, Navalny tweet)

MOSCOW, July 1 (Reuters) - A Moscow court jailed Russian opposition leader Alexei Navalny for 10 days on Monday after finding him guilty of breaking the law when he took part in a street demonstration last month.

The Kremlin critic was among more than 500 protesters detained by police while rallying in Moscow to call for the punishment of police officers involved in the alleged framing of a journalist.

The protest came after police abruptly dropped drug charges against investigative journalist Ivan Golunov, a rare U-turn by the authorities in the face of anger from his supporters who said he was targeted for his reporting.

The authorities had hoped freeing Golunov and promising punishment for those who allegedly framed him would appease his supporters but they decided to go ahead with a protest nonetheless.

"Ten days of detention for a rally against arbitrariness," Navalny wrote on Twitter after the verdict. "It's unpleasant, but I think I did the right thing. If we remain silent and sit at home, the arbitrariness will never stop."

Navalny, Russia's most prominent opposition figure, has served several stints in jail in recent years for organising anti-government demonstrations.

The European Court of Human Rights in November ruled that Russia's repeated arrests and detention of Navalny in 2012 and 2014 were politically-motivated and breached his human rights, a ruling Moscow called questionable. (Reporting by Mikhail Antonov and Lev Sergeev Writing by Tom Balmforth and Gabrielle Tétrault-Farber Editing by Mark Heinrich)