Filipino police investigators look for evidence at the site of a bomb explosion outside the airport terminal building in Zamboanga City on August 5, 2010. (AFP)

ZAMBOANGA, Philippines (AFP) – A politician who survived a "human bomb" attack that left two people dead in the volatile Mindanao region said Friday he believed his rivals had tried to assassinate him.

The blast occurred at Zamboanga city airport on Thursday as Sulu province governor Sakur Tan and other passengers on a flight from Manila were leaving the terminal, killing a man carrying the bomb and a bystander.

"It is not just a coincidence that this bomb exploded right next to me," said Tan, 60, who suffered only minor injuries but whose son was hit by the severed head of the man carrying the bomb.

A total of 24 people were injured, including an elderly British man who lived in the area, police said.

Tan told ABS-CBN television he believed rival politicians with links to "terrorists" orchestrated the attack, and that he suspected the same people were behind an attempt on his life in May last year.

"I received intelligence reports that I would be bombed," said Tan, who rules over the Sulu island chain about 100 kilometres (60 miles) south of Zamboanga.

Both areas are part of the impoverished Mindanao region, where deadly Muslim and communist insurgencies have raged for decades.

The US military also has about 500 soldiers stationed in Mindanao to help local forces combat the Al Qaeda-linked Abu Sayyaf, an Islamic militant group blamed for the Philippines' worst terrorist attacks.

The Philippine military confirmed that one of the men killed was carrying the bomb, but said they doubted it was a suicide attack and that he may have been duped into carrying the deadly device.

Two ID cards found on the dead man identified him as a local construction worker who was not affiliated with any extremist groups, regional military commander Lieutenant-General Benjamin Dolorfino told AFP.

"The indications are it is not a suicide bomber. The possibility is someone sent (the man) with the backpack and he did not know what was inside," Dolorfino said.

"You can see him on (security video footage). He was just standing outside the airport arrival area just before the blast. He was just loitering there."

Dolorfino also said there was nothing to immediately suggest the Abu Sayyaf was behind Thursday's attack, and that the militants had no history of suicide bombings.

He said it may have been directed at Tan but it also may have been linked to a planned visit to Zamboanga on Friday by the US ambassador to the Philippines, Harry Thomas.

Asked about the nature of the blast, Tan said: "I really would not know if it was a suicide bombing or was it triggered by someone else. But it was a human bomb."

Presidential spokesman Ricky Carandang said authorities did not yet know the motive behind the attack.

Thomas, who was set to inspect local projects funded by US aid money, immediately cancelled his trip.

The Philippines has long suffered from political violence, and many powerful politicians command "private armies" to violently enforce their will against critics and opponents.

In the worst case of such violence, 57 people were murdered in Maguindanao province, which is also part of Mindanao, in November last year allegedly by the private army of the political clan that ruled the area.