MOSCOW (AP) — FIFA general secretary Jerome Valcke insists Russia's preparations to host the 2018 World Cup remain "on track" despite delays to some stadiums.

The completion date for the stadium in the city of Rostov has been pushed back seven months to December 2017, while sports minister Vitaly Mutko has also identified problems at arenas in Volgograd and Nizhny Novgorod.

Valcke said during a visit to meet local World Cup organizers that "we're working very well together, we're on track for all the preparation, not only for the World Cup but also for the Confederations Cup in 2017."

The four stadiums for the Confederations Cup will all be "absolutely ready" by May 2016, Mutko said, including the much-delayed and costly St. Petersburg stadium, originally scheduled to open in 2008.