ISTANBUL (AP) -- Turkey's Justice Minister Bekir Bozdag says at least 31 people have been killed and some 147 wounded in the attack on Istanbul's Ataturk airport.
Another senior government official says the death toll could climb much higher.
The senior official at first said close to 50 people had already died, but later said that the figure was expected to rise to close to 50.
The official, who spoke on condition of anonymity in line with government protocol, also said all initial indications suggest the Islamic State group was behind the attack.
Bekir Bozdag said that according to preliminary information, "a terrorist at the international terminal entrance first opened fire with a Kalashnikov and then blew himself up."
Another official said two attackers detonated explosives at the entrance of the international terminal after police fired at them.
The official, who spoke on condition of anonymity in line with government protocol, said he was citing information from the interior ministry. It wasn't immediately clear why his account of the number of attackers was different to the justice minister's.
The official said the attackers blew themselves up before entering the x-ray security check at the airport entrance.
Turkish airports have security checks at both at the entrance of terminal buildings and then later before entry to departure gates.
Eye witness Ercan Ceyhan told CNN-Turk that he saw some 30 ambulances enter the airport.
The private DHA news agency said the wounded, among them police officers, were being transferred to Bakirkoy State Hospital.
Turkey has suffered several bombings in recent months linked to Kurdish or Islamic State group militants.
The bombings included two in Istanbul targeting tourists -- which the authorities have blamed on the Islamic State group.
The attacks have increased in scale and frequency, scaring off tourists and hurting the economy, which relies heavily on tourism revenues.
Jim Hyong Lee of South Korea told the Telegraph he and his family were checking in for a flight home when "we heard gunshots."
"I grabbed my family and ran," Lee said. "Someone waved us into the prayer room and hid us there until the police came."
Roads around the airport were sealed off for regular traffic after the attack and several ambulances could be seen driving back and forth.