By Manuel Mogato and Karen Lema

MANILA (Reuters) - Former Philippine dictator Ferdinand Marcos was buried with military honors at a heroes' cemetery in Manila on Friday, almost 30 years after his death in Hawaii, amid scattered protests around the sprawling capital.

Many in the Philippines are angered by the way Marcos's family had kept the timing of the burial secret, including Vice President Leni Robredo who likened the ceremony to "a thief in the night".

"This is nothing new to the Marcoses - they who had hidden wealth, hidden human rights abuses and now hidden burial - with complete disrespect for the rule of law," Robredo, who belongs to an anti-Marcos political party, said in a statement.

President Rodrigo Duterte, who is attending the Asia Pacific Economic Cooperation summit in Lima, Peru, had given orders in August that the burial could go ahead, fulfilling an election campaign promise.

But it only took place after a Supreme Court ruling last week that dismissed objections from human rights groups.

"I was just being legally strict about it," Duterte said in Lima, defending his decision to allow the burial.

"President Marcos was a president for so long and he was a soldier. So, that's about it. Whether or not he performed worse or better, there is no study, there is no movie about it. It's just the challenges and allegations of the other side which is not enough."

Marcos's eldest daughter, Imee Marcos, the governor of Ilocos Norte province, thanked Duterte for allowing her father, a former soldier and guerrilla leader during World War Two, to be laid to rest with soldiers.

"At last, my beloved father's last will to be buried with fellow soldiers was fulfilled today," she said. She also asked people to understand the family's decision to keep the ceremony "simple, private and solemn".

The media was banned from the ceremony and waited outside the cemetery as a 21-gun salute was fired and a Philippine flag was handed to Marcos' widow, Imelda.

Thousands of protesters rallied around Manila, some burning pictures of the late ruler.

Past governments had blocked the burial, because they were either led by enemies of Marcos or bowed to public opinion, and the body had lain in a refrigerated mausoleum in Marcos's hometown of Paoay since its return to the Philippines in the early 1990s.

"At a time like this, it is fitting that we hear the voices of others: learn about their stories, the persons behind the statistics, their loved ones lost to the regime of martial law," said Duterte's predecessor, Benigno Aquino, whose father and namesake was assassinated during Marcos's rule.

Marcos had imposed martial law in 1972, before the end of his second term as president and ruled by decrees.

He ruled the Philippines for 20 years, during which time he, his family and cronies amassed an estimated $10 billion in ill-gotten wealth, a commission found. Tens of thousands of suspected communist rebels and political foes were killed.

He was chased from office in a people's power revolt in 1986 and died in exile in Hawaii three years later. The Marcos family returned to the Philippines in the 1990s and became powerful politicians representing his home province of Ilocos Norte.

(Additional Reporting By Roli Ng, Peter Blaza and Romeo Ranoco; Editing by Nick Macfie)