Gen. Sani Abacha, 54, the reclusive Nigerian who drew worldwide condemnation for his authoritarian rule over Africa's most populous nation, died June 8, reportedly of a heart attack.

For a man who spent years on the world political stage, Gen. Abacha died a remarkable unknown, even in his own country. He appeared infrequently in public, and when he did, he said little. Whether he was dressed in a medaled military uniform or in the traditional, flowing robes of his native northern Nigeria, his eyes often were obscured behind aviator-style sunglasses. In portraits, his face was impassive, marked by two ritual tribal scars down each cheek.

Even by the standards of Nigeria's long history of army rulers, Gen. Abacha was notable for a tough, silent exterior that gave little hint of his own thoughts and appeared to care little for those of others.

After taking power in a 1993 coup, Gen. Abacha brushed aside the condemnations and economic sanctions of Western governments. When his chief civilian rival, Moshood Abiola, challenged him by claiming to be the rightful ruler of Nigeria, Gen. Abacha jailed him and again ignored the protests.

The next year, 1995, Gen. Abacha oversaw the execution of nine political and environmental rights activists, including the writer Ken Saro-Wiwa, who opposed the government's oil production methods in the Niger delta.

Gen. Abacha "advanced in the military through the coup d'etat," having taken part in three of them between 1983 and 1993, said a Western diplomat who asked not to be identified. "He knew that any sign of weakness might encourage some young officer to rise against him, too."

When Gen. Abacha spoke, he did so softly, slowly and with apparent care, interlocutors said. He appeared convinced that the United States and other Western powers were conspiring to keep Nigeria -- and thus Africa -- as powerless as possible in world affairs, said an African diplomat who met with him and spoke on the condition of anonymity.

Gen. Abacha "isn't worried by what the outside world thinks," the diplomat said in an interview last month. "He is a self-made man who believes that most African leaders -- including {South African President Nelson} Mandela -- have been corrupted by a desire to please the United States and the West.

"He sees himself and {Libyan leader Moammar} Gadhafi as the only true African nationalists," the diplomat said.

Gen. Abacha was born in 1943, a member of the Kanuri ethnic group, based in northeast Nigeria. Some official sources list him as having been born in Kano, which, as the traditional political power center of the north, would have been a more auspicious origin. But Nigerian scholars and foreign diplomats say he and his family came from the northeast, near the city of Maiduguri.

Little is known of Gen. Abacha's early military career. Like many Nigerian officers of his generation, he pursued training courses in the United States and Britain. He first came to public attention in 1983 as the officer who broadcast the announcement of the military coup by Gen. Muhammad Buhari.

Buhari's successor, Gen. Ibrahim Babangida, made Gen. Abacha his defense minister and relied on him to control the ambitions of younger military officers. Babangida began losing control in 1993 when he, with Gen. Abacha's help, scuttled a promised return to civilian government.

Babangida handed power to a caretaker civilian administration, although not without first forcing the retirement of several army officers who rivaled Gen. Abacha. With the ground thus prepared, Gen. Abacha took power outright a few months later. Gen. Abacha died in the middle of a political struggle over his campaign to remain in power by having himself elected as a civilian president. While Gen. Abacha had been seen little in recent months, his aides had led a campaign declaring that he was the only man qualified to lead the nation of more than 100 million people.

Gen. Abacha is survived by his wife, Maryam, and nine children.