Military helicopters fly over the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9. (Photos: Xinhua)

Self-propelled howitzers roll down the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicemen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicemen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian military cadets march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian Defence Minister Sergei Shoigu (front) takes part in a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian military cadets march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019. The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Members of Russian honor guard take part in a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019.

The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019.

Russian servicewomen march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019.

The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Soldiers march on the Red Square during a rehearsal for the Victory Day parade in Moscow, Russia, May 7, 2019.

The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.

Soldiers attend the Victory Day parade rehearsal in Moscow, Russia, on May 7, 2019.

The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9. (Xinhua/Evgeny Sinitsyn)

The 74th anniversary of the victory over Nazi Germany in World War II will be marked here on May 9.