Petro Poroshenko, addressing parliament, said there is a "colossal threat" of an upsurge in attacks by pro-Russia separatists and a "full-scale invasion" by Moscow's forces.
The system was considered a triumph by the Soviets, but was built by the same ruthless means that helped cause a famine, which killed millions in the 1930s.
The launch is the latest in a string of failures for the Proton-M rocket, a workhorse for the International Launch Services, a joint Russia-American satellite carrier business.
A decade ago, President George W. Bush was among those who visited Moscow for the occasion. Today, the event highlights the friction between Russia and the West.
Robert Siegel talks to Bill Browder, an American financier who was expelled from post-Soviet Russia and saw an attempt to claim his company devolve into a deadly bureaucratic and legal farce.
Cyberwarfare is a hidden world with few documented examples. In a new report, security researchers detail digital attacks against Ukraine's military and charge the Russian military as the hacker.
The cargo ship was launched Tuesday and scheduled to dock at the International Space Station to deliver 2.5 tons of supplies. Ground control lost contact after the ship reached its first orbit.