The number of confirmed deaths from the A(H1N1) influenza virus in the US rose to nine after the death of a young man in Utah, the federal Centres for Disease Control and Prevention (CDC) said on Thursday.
The CDC put the total number of confirmed infections with the new virus in the US at 5,764.
The Utah Health Department said in a statement on Wednesday that "a Salt Lake County resident between the ages of 18 and 25" had died of the disease. This was the first H1N1 flu death in the state.
Local radio station KSL reported online that the victim was a 21-year-old man who had respiratory problems prior to being infected with the virus.
The Arizona Health Department on Wednesday confirmed the death of a 13-year-old boy and said in a statement that he died March 15 of "complications of the H1N1 virus". This had not been included in the CDC's tally by Thursday and would be the 10th US swine-flu death.
The boy had not travelled recently, Arizona health officials said. Several members of his family had also contracted the virus but recovered, with the exception of one sibling who remained hospitalised.