At least 28 people killed in suicide bombing attack on Turkey's biggest airport
People stand outside the entrance as they leave the airport after two explosions followed by gunfire hit the Turkey's biggest airport of Ataturk in Istanbul, on June 28, 2016. (Agence France-Presse/Ozan Kose)

At least 28 people were killed Tuesday evening in a suicide attack at the international terminal of Istanbul's Ataturk airport, the city's governor said.

Two explosions hit the airport -- Turkey's biggest -- followed by gunfire, local television channels reported, adding that all flights had been suspended.

Sixty people were wounded, six of them very seriously, state news agency Anadolu said.

More than a dozen ambulances raced to Ataturk airport, CNN Turk said.

The channel cited witnesses as saying two violent blasts shook the international terminal, sparking panic among passengers.

"It was very strong, everyone panicked and started running in all directions," one witness told CNN Turk.

Police set up a perimeter around the site, television images showed.

Turkey has been hit by a string of deadly attacks in the past year, blamed on both Kurdish rebels and the Islamic State jihadist group.

The Turkish airport attack also follows coordinated suicide bombings at Brussels airport and a city metro station in March that left 32 people dead.

- Attacks on Istanbul -

Istanbul, a major tourism hub that is home to some 15 million people, has suffered several attacks in recent months, including a bombing in the heart of the tourist district that killed a dozen German visitors and was blamed on IS.

Two months later, three Israelis and an Iranian were killed in a bombing on the city's main Istiklal shopping street, an attack also blamed on IS.

A blast on the tarmac at the other Istanbul airport, Sabiha Gokcen, killed a cleaner and wounded another in December, damaging several planes.

Located just outside Turkey's biggest city, Ataturk airport served more than 60 million passengers in 2015, making it one of the busiest in the world.

Turkey has been hit by at least five attacks blamed on IS jihadists, including a blast in Ankara in October 2015 that left over 100 dead.

However, IS extremists have never formally claimed responsibility for an attack in Turkey.

Turkey was long accused by its Western partners of turning a blind eye to the dangers posed by IS but has in recent months considerably stepped up police raids on the group's cells in the country.

Ankara has meanwhile launched a sustained offensive against the outlawed rebel Kurdistan Workers' Party (PKK) following the collapse of a ceasefire last year.

Hundreds of members of the Turkish security forces have been killed in PKK attacks since the truce collapsed.

More than 40,000 people have been killed since the PKK took up arms in 1984 demanding a homeland for Turkey's biggest minority.

The group is regarded as a terrorist organisation by Ankara and its Western allies.