HARTFORD, Conn. — Power crews were still working Saturday to restore electricity to thousands of customers after a powerful Halloween storm knocked trees and limbs onto wires, days after a coalition of cities and towns warned that Connecticut municipal officials face an "environmental crisis" of diseased trees.

Connecticut Conference of Municipalities Executive Director Joe DeLong sent a letter Thursday to Democratic Gov. Ned Lamont, seeking additional resources and help dealing with the fallout of trees infested and subsequently weakened by emerald ash border beetles and gypsy moth caterpillars, as well as drought.

"Municipal officials believe that this crisis shows no sign of abating in Connecticut," CCM Executive Director Joe DeLong said. "This is a bona fide public safety, public health, and environmental crisis for the most affected towns and cities."

Crews from Eversource finished restoring power to dozens of customers in Marlborough who were still without power on Saturday. Town officials blamed the unusually high tree damage on insects that ate their way through the tree-lined community, making the trees brittle and unable to withstand Thursday's high winds. DeLong noted in his letter to Lamont that Marlborough has been spending $100,000 a year to remove dangerous trees and large limbs on town property, while the state Department of Transportation and Eversource have also been removing trees.

By late afternoon on Saturday, Eversource still reported more than 3,500 customers without power, but the company said its hundreds of crews were "making good progress" restoring the electricity.

"Some of the winds were reported to be over 60 mph, bringing down trees and limbs onto power lines," Eversource said. "Despite challenging conditions, Eversource has already restored power to more than 145,000 Connecticut customers since Thursday night."

CCM warned Connecticut can expect electric rates to rise if similar wide-spread power outages occur in the coming months.

CCM is recommending Lamont create a working group of state and local officials and utilities representatives to come up with a plan to address tree infestation, as well as include funds for tree removal in the yet-to-be-finalized state bond package. The organization is also calling for the governor to expand eligibility for certain state grants for tree infestation and reduce the "red tape" towns experience when trying to obtain state permits to burn tree debris.