(Adds quotes, Russian criticism, Ukraine ombudswoman)
KIEV, July 25 (Reuters) - Ukraine's security service said on Thursday it had detained a Russian tanker in the Ukrainian port of Izmail for its alleged involvement in an incident in November in the Kerch Strait that led to Russia seizing three Ukrainian vessels.
"The Ukraine security service and military prosecutors' office detained (a) Russian tanker, the Neyma, which had blocked Ukrainian warships in the Kerch strait," the security service said in a statement on Thursday.
Russia captured the vessels and their crews in waters that separate the Crimean peninsula, which Moscow annexed from Ukraine in 2014, and Russia.
The Ukrainian security service said the vessel had entered Ukraine under its new name, the Nika Spirit, "to cover its involvement in illegal actions", but that it had identified the ship by its unique International Maritime Organization number (IMO).
"The above named vessel is considered to be a piece of material evidence, (and) a petition to a court for its arrest is being prepared," the security service said in its statement.
In Moscow, senior Russian lawmaker Vladimir Dzhabarov described Ukraine's detention of the tanker as "absolutely illegal" and said it was detrimental to relations between the two countries, RIA news agency reported.
In Kiev, Ukraine's ombudswoman said negotiations on the release of the Ukrainian sailors from the three vessels seized by the Russian navy off Crimea's coast had intensified after Russian and Ukrainian leaders spoke by phone earlier this month. (Reporting by Polina Ivanova, Pavel Polityuk and Writing by Tom Balmforth Editing by Mark Heinrich)