TOKYO (AP) _ Japanese Ambassador Morihisa Aoki, held captive in his Lima residence by Peruvian guerrillas, has been in risky situations before and is not intimidated by danger, his brother said today.

Though Aoki's family has not had any direct contact with the ambassador since the rebels stormed his residence Dec. 17, the younger Aoki said relatives have faith he will ride out the crisis.

``We just want him to do his best,'' Morikuni Aoki, 56, told The Associated Press in his Tokyo apartment.

Aoki was heartened by the rebels' release of 225 hostages Sunday night, even though the ambassador, 58, was not among them.

``It proves the terrorist group isn't that extreme,'' said Aoki, whose brother is now among 140 people still held. ``Things are moving in a good direction. I feel relieved.''

The ambassador comes from a family of diplomats. His great-grandfather, Shuzo Aoki, served as Japan's ambassador to the United States and as foreign minister. His father and maternal grandfather were also diplomats.

``Of course, he knew danger was possible,'' Aoki said of his brother.

Ambassador Aoki has served in Hong Kong, the United Nations, the Philippines and Vietnam during three decades in the foreign service, his brother said. Peru was his first posting as ambassador.

``He was in Vietnam during the war there, so he's used to danger,'' Aoki said.

Aoki said his brother's professional poise was clear in telephone interviews with Japanese national broadcaster NHK at the beginning of the hostage crisis.

``I thought he was really calm,'' Aoki said.

Still, the ordeal has taken its toll on Aoki, the ambassador's only sibling, and their 80-year-old mother.

``There's nothing we can do from here,'' Aoki said.