WASHINGTON (AP) — President Donald Trump said Thursday that federal officials are developing guidelines to rate counties by risk of virus spread, as he aims to begin to ease nationwide guidelines meant to stem the coronavirus outbreak.

In a letter to the nation’s governors, Trump said the new guidelines are meant to enable state and local leaders to make “decisions about maintaining, increasing, or relaxing social distancing and other measures they have put in place.” States and municipalities would still retain authority to set whatever restrictions deem necessary.

Trump has been seeking for days to determine how to contain the economic fallout of the guidelines issued by his administration as well as local leaders to slow the tide of infections. Last week he unveiled a 15-day program advising against large gatherings and calling for many Americans to remain at home — and many states have placed even greater restrictions on their residents.

Trump said the rollout of new testing will enable more nuanced recommendations that would allow some lesser-impacted parts of the country to regain a sense of normalcy sooner.

“Our expanded testing capabilities will quickly enable us to publish criteria, developed in close coordination with the Nation’s public health officials and scientists, to help classify counties with respect to continued risks posed by the virus,” Trump said.

Earlier Thursday, Trump held a conference call with the nation’s governors to update them on the federal government’s response.