The Biden administration has declared the cities and towns that suffered “catastrophic damage” from flooding in Massachusetts last September won’t be receiving help from the feds, but the governor and at least one mayor have indicated they will continue to fight for assistance.

Leominster Mayor Dean Mazzarella, in a Tuesday memo, called it “almost unbelievable” that the Federal Emergency Management Agency has denied Gov. Maura Healey’s request for President Biden to declare a major disaster in Bay State communities hit hard by the “devastating floods.”

Mazzarella said his city worked with the Massachusetts Emergency Management Agency for three months following the storm, compiling information that showed how the floods caused $35 million in city damage, affecting 1,400 homes and businesses.

“Whether it was additional information on individual homes, businesses, or city damage, we worked night and day to get every piece of information they requested to them by each deadline that was set,” Mazzarella said. “Yet, President Biden and FEMA opted not to approve the declaration.”

“We are not done. Leominster has never backed down from a challenge and this is no exception,” the mayor added.

Heavy rains and flooding left roads and homes damaged in Leominster and North Attleboro and prompted Healey to declare a four-day state of emergency as crews worked to clean up the municipalities. The storms required evacuations, water rescues, and the construction of temporary roadways so first responders and residents could access homes.

Attleboro, Lancaster, Princeton, Springfield and Sterling also received support from MEMA during their recovery.

Healey submitted the request for the disaster declaration in December, with the governor looking to open the door to a FEMA-run program that provides federal assistance for individuals and public infrastructure. MEMA works with federal counterparts to assess potentially reimbursable damages caused by or related to a disaster.

Hazard mitigation assistance, which provides dollars to reduce disaster losses, is also made available.

But in a letter sent to Healey on Sunday, FEMA Administrator Deanne Criswell alerted the governor that her request for a major disaster declaration had been denied.

“Based on our review of all of the information available, it has been determined that the damage from this event was not of such severity and magnitude as to be beyond the capabilities of the state, affected local governments, and voluntary agencies,” the letter states. “Accordingly, we have determined that supplemental federal assistance is not necessary.”

Criswell outlined how the denial may be appealed within 30 days, and the feds will “communicate any additional resources that may be available through other federal agencies and/or volunteer organizations to address unmet needs for survivor assistance.”

“Our administration is deeply disappointed that FEMA denied our request for a major disaster declaration for damage caused by extreme weather in September,” Healey’s spokesperson Karissa Hand said in a statement. “We submitted a strong request based on the severe local impacts this storm had on our communities. We plan to appeal this decision and will do everything we can to continue our advocacy with our federal partners and support our communities.”

So far this year, Biden has declared major disasters in Michigan, Maine, West Virginia, New York and Rhode Island for storms, tornadoes, flooding, landslides and mudslides that wreaked havoc on those states last year.

Biden declared a state of emergency in Massachusetts last September after months of seemingly endless rain and the unanticipated flooding in Leominster, North Attleboro and elsewhere.

Heavy storms and torrential downpours soaked farms and fields last July, leaving more than 1,000 acres of crops destroyed and farmers scrambling to survive after losing crops that were near ready to harvest. Months later, 37 municipalities in Berkshire, Worcester, Franklin, Plymouth, Norfolk, Middlesex, and Essex Counties were selected to receive a portion of $10 million in disaster relief.

The disaster relief funding was included in a spending bill Healey signed in December. That pool of money includes $5 million in flood relief funding that the governor is directing her administration to “quickly” distribute.

In Leominster, officials have hired a consultant to “assist us with the appeal and the governor personally assured me last night that her team is in this fight with us,” Mazzarella said in his memo Tuesday.

“You have my word that we will continue to fight for this declaration,” he said. “The City of Leominster and the other communities with damage deserve this assistance.