By Jason Bush MOSCOW (Reuters) - Russian police detained around 30 pro- and anti-gay activists in central Moscow on Saturday, imposing the city's ban on gay rights demonstrations. The arrests, underlining Russia's tough response to public demonstrations by gay groups, coincided with the first ever gay rally in neighboring Ukraine, which was allowed by the authorities and protected by the police. Russia's parliament has given preliminary approval to a ban on "homosexual propaganda" targeting minors, which critics say would effectively ban gay rights demonstrations. ...