China's health ministry says two people who received vaccinations for swine flu have died though at least one of the death appears to be unrelated.

A statement posted on the ministry's Web site late Friday says an autopsy showed one of the two people suffered a heart attack. An autopsy on the other is still to be conducted.

It says experts have "basically ruled out the possibility" that the heart attack victim's death was the result of an allergic reaction to the flu vaccine.

But it adds experts are waiting for more lab results.

The ministry has said more than 13 million Chinese have received the swine flu vaccine so far. The statement says the vaccines are generally safe and vaccinations will continue.