NEW YORK: US Treasury yields fell on Thursday as the rapid spread of coronavirus cases across some American states weighed on risk sentiment, even as data showed US economic improvement.

A surge in COVID-19 infections in numerous US Southern states has raised concerns that new business shutdowns meant to stem the spread of the virus will cause fresh economic damage.

"The next two months are really critical, can the economy survive this surge in COVID cases in the Sunbelt, is that surge going to manifest itself elsewhere too," said Tom Simons, a money market economist at Jefferies in New York.

"The risk of owning some protection is relatively low and I think that's generally the bias. You want to have some Treasuries no matter what," Simons added.

Benchmark 10-year notes fell two basis points to 0.614%. They have held in a tight range from 0.569% to 0.784% since mid-June.

The yield curve between two-year and 10-year notes flattened one basis point to 46 basis points.

Bonds rallied even after US data showed recent improvement in the economy.

US retail sales increased by 7.5% in June, which was more than economists expected. The Labor Department showed 1.30 million people filed for state unemployment benefits during the week ending July 11, slightly down from 1.31 million in the prior period.

A gauge of manufacturing activity in the US Mid-Atlantic region also jumped in July.

Bonds had earlier gained after data in China showed unexpected weakness in domestic consumption.