Japan has confirmed bird flu affected chickens on a farm in the south of the country.

Also, an Indonesian health official announced Saturday the recent deaths of two women from Avian influenza. Two other people died earlier in the week.

A fresh outbreak of avian influenza is also feared in Nigeria.

Japanese officials confirmed Saturday that bird flu caused the deaths of more than two-thousand chickens at a farm 900 kilometers southwest of Tokyo.

The officials have not determined whether this particular strain of bird flu is the feared H5N1 or another less deadly form.

However, they announced the culling of the remaining 10,000 birds at the farm as a precaution against the virus spreading.

Meantime health officials in Indonesia say two more people have died from bird flu there this week, raising the country's total number of deaths to at least 61.

Both women had received treatment in the same hospital in Indonesia's capital of Jakarta.

Earlier in the week, a 37-year-old woman and teenage boy died from bird flu.

Although three of this week's victims were from the same village, Indonesia's Ministry of Health has said none of them were known to have had contact with each other.

Jakarta hospital spokesman Mukhtar Ikhsan says they are also treating the son of the 37-year-old woman for the virus. He says, 'This is a confirmed bird flu infection, and at the moment his condition is deteriorating.'

Nigerian officials meanwhile are investigating a suspected fresh outbreak of avian influenza in two northern states. Thousands of birds have been culled to prevent the virus from spreading.

At least one confirmed case of the deadly H5N1 strain of avian influenza has been reported in Sokoto state.

In nearby Katsina, at least two suspected cases are being investigated.

Dr. Garba Sharabutu, a veterinarian and president of the Nigerian veterinarian association, who is in Sokoto to help contain an outbreak, says sufficient steps have been taken.

'We have one [case] that has been confirmed in one of the farms here in Sokoto,' said Dr. Sharabutu. 'Right now, we have moved most of our people there. And, they are actually doing the stamping out, trying to control the disease within the farm. They are really spraying the farm, and they have killed all the birds and buried them properly.'

Experts say bird flu has become endemic in Nigeria since it was first detected about a year ago, despite the government's claim the disease has been wiped out.

A number of states have reported suspected cases in the last few months, prompting fears that a major resurgence is inevitable.

Dr. Sharabutu says the authorities have risen to the challenge this time, and appear keen to check the possible spread of the virus.

'The federal [government] might moved to Sokoto,' added Dr. Sharabutu. 'They are there, trying to control things. The state governor is doing his best. Yesterday, we had sensitization workshop in Sokoto. So, with these renewed efforts, I am definitely sure something may come out of it.'

More than 450,000 infected chickens have been slaughtered in Nigeria since last year, but no human case has so far been reported.

Currently, bird flu remains difficult for humans to catch. But international experts fear the virus could mutate into a form that could spread easily among humans.