MOSCOW, Jan. 24 (Xinhua) -- At least 31 people were killed and over 130 were injured in an explosion at Moscow's Domodedovo airport on Monday, the Russian Health Ministry said。

　　The Russian Investigative Committee's Transport Investigative Department has confirmed that an explosion occurred at Domodedovo Airport's luggage reclaim zone at the international arrivals terminal。

　　"According to available information, an explosion occurred at Domodedovo's arrivals hall at 16:22 Moscow time (1322 GMT)，" a spokeswoman for the investigation committee, Tatyana Morozova, said。

　　The preliminary reports suggest that it might be a suicide bombing, a source told local media。

　　The Health Ministry said among the 130 injured, 20 are in serious condition。

　　Eyewitnesses said there is a heavy smoke at the Moscow airport and the entry from the arrivals zone has been closed。

　　A source said the blast was equivalent to some 5 kg of TNT。

　　Moscow police has tightened the security in the city's other airports and metro system。

　　新华网莫斯科1月24日电(记者 耿锐斌)俄罗斯莫斯科的多莫杰多沃机场24日发生爆炸，已至少造成31人死亡，130多人受伤。

　　据俄媒体报道，当地时间16时32分(北京时间21时32分)，多莫杰多沃机场抵达大厅内发生爆炸。有消息说，这是一起自杀式炸弹爆炸。