MOSCOW, May 29. /TASS/. Explosions are audible in central Kiev on Monday, and smoke is also visible near the city's Zhulyany Airport, eyewitnesses told TASS.

"Explosions can be heard in the center of the city. An air-raid alert has been declared; the air defense system has been activated," the eyewitness said.

As another source pointed out, "smoke can be seen coming from the direction of Zhulyany Airport."

More than ten explosions have been heard in the capital city, and people began to descend into the subway and basements, another eyewitness said. "More than ten explosions in the center, the air defense system is activated, people are panicking, going down into the subway and basements," the source said.

Earlier on Monday, Kiev Mayor Vitaly Klitschko said that several explosions had occurred in the capital. A little later, the mayor said that first responders are working at the scene of the explosions. In addition, Klitschko noted that a fire is being extinguished in the Obolonsky District, which was sparked by falling rocket debris. In turn, the Kiev regional military administration reported that the air defense system had been activated.

At the moment, an air raid alert has been declared in most parts of Ukraine, including Kiev.