* Navy helicopter was flying VIPs to Port Harcourt
* Residents in volatile Kaduna nervous
* Authorities decline to speculate on cause of crash (Adds presidency statement, Kaduna mood, background)
By Owolabi Tife
YENAGOA, Nigeria, Dec 15 (Reuters) - The governor of Nigeria's volatile Kaduna state and a former national security adviser were among six killed when a helicopter crashed in the southerly oil-producing Bayelsa state on Saturday, officials said.
The helicopter wobbled in the sky before nose-diving into a forest in Ogbia Creek at around 3:30 p.m. (1430 GMT), a local resident who witnessed the crash told Reuters.
"By the time we got to the scene it was in flames," said Hitler Adunion, a local community leader. "We tried to put them out but it was difficult. We saw the roasted bodies of those inside."
The Nigerian Navy confirmed that its Agusta helicopter had crashed while carrying VIPs to Port Harcourt but it didn't give a reason and civilian authorities declined to speculate on the cause. President Goodluck Jonathan ordered an investigation.
"(The) President has expressed utter shock and sadness over the crash ... (he) extends deep and heartfelt condolences to the families and friends of the deceased," a statement from the presidency said.
The statement confirmed the deaths of Kaduna state governor Patrick Ibrahim Yakowa, former national security adviser General Owoye Azazi, their aides Dauda Tsoho and Mohammed Kamal and the two pilots, Muritala Mohammed Daba and Adeyemi Sowole.
Yakowa won a tight vote last year to become Kaduna's first Christian governor, under the ruling People's Democratic Party ticket. He replaced Namadi Sambo, who is now vice president.
Kaduna sits on the borderline between the mostly Christian south and the largely Muslim north of Africa's most populous nation and has been at the heart of religious conflict.
Hundreds of people were killed in Kaduna state in clashes between ethnic and religious groups last April after Jonathan, a Christian southerner, won a presidential vote against his Muslim northern rival Muhammadu Buhari.
Kaduna was quiet on Saturday evening but some residents said they were nervous.
"I just had to rush down to my house because this is Kaduna state and anything can happen, we can't forget the election crisis when a lot of lives and properties were lost," local resident Maxell Danjuma told Reuters.
Islamist sect Boko Haram has bombed several churches in Kaduna since an uprising in 2009. The sect has killed hundreds this year in its effort to carve out an Islamic state in a country of 160 million split between Christians and Muslims.
The 36 state governors are among the most powerful politicians in Nigeria, Africa's biggest oil producer, often controlling budgets bigger than those of many African countries.
Azazi had been a close adviser to Jonathan but was sacked in June as Nigeria struggled to stem Boko Haram's attacks, which focus on politicians, security forces and religious targets.
Several high-profile politicians had travelled to Bayelsa, Jonathan's home state, this weekend for a funeral.
Like many African countries, Nigeria has a poor air safety record.
Nigeria's deputy police chief and three other officers were killed when a helicopter crashed in the central city of Jos in March.
In June, a passenger plane crashed into a densely populated part of Lagos, Nigeria's commercial hub, killing 163 people. (Additional reporting by Isaac Abrak, Camillus Eboh, Felix Onuah and Segun Owen; Writing by Joe Brock; Editing by Stephen Powell)