LOME, Togo — The president of Togo, Africa's longest-ruling leader, died unexpectedly Saturday as he was being rushed to Europe for treatment of a heart attack, officials said.

President Gnassingbe Eyadema, 69, suffered a heart attack early Saturday in his hometown of Piya in southeastern Togo and later died, said Barry Moussa Barkue, special adviser to the president.

Prime Minister Koffi Sama went on state radio and announced that Eyadema died on his way to Europe for treatment of the heart attack.

Sama called upon the security forces to keep law and order.

He also announced all land and air borders to the tiny West African country had been closed.

Eyadema has ruled the West African nation since the 1960s, when he came to power following Africa's first postcolonial coup. Only Cuba's Fidel Castro has been in power longer. Eyadema was last re-elected in a May 2003 vote.

According to Togo's constitution, the speaker of parliament, Fanbare Tchaba, succeeds the president in the event of his death, but there was no official statement announcing Eyadema's successor.

State radio played mourning music, interrupted by Sama's comments.

Barkue said the death was unexpected. He said Eyadema looked "hearty and even granted audience to visitors yesterday (Friday). So his sudden death is unbelievable."

There had been no reports in recent weeks of any illnesses.