Russia presses invasion to outskirts of Ukrainian capital. #AP

Russia pressed its invasion of Ukraine to the outskirts of the capital Friday after unleashing airstrikes on cities and military bases and sending in troops and tanks from three sides in an attack that could rewrite the global post-Cold War security order.

Explosions sounded before dawn in Kyiv and gunfire was later heard near the government quarter as Western leaders scheduled an emergency meeting and Ukraine’s president pleaded for international help to fend off an attack that could topple his democratically elected government, cause massive casualties and ripple out damage to the global economy.

Among the signs that the Ukrainian capital was increasingly threatened, the military said Friday that a group of Russian spies and saboteurs was seen in a district of Kyiv about 5 kilometers (3 miles) north of the city center. Earlier, the military said that Russian forces had seized two Ukrainian military vehicles and some uniforms and were heading toward the city to try to infiltrate under the guise of being locals.