Federal Realty executives say it’s likely they’ll break ground on more office space and multifamily housing at Somerville’s Assembly Row by next spring.

During a conference call to discuss the company’s quarterly earnings, executives said they are accelerating plans to develop two of the five remaining development parcels at Assembly Row within the next one or two quarters.

Federal Realty has approvals for another 2 million square feet of office and/or lab space and 826 residential units at Assembly Row. It’s been marketing a build-to-suit office-lab parcel via JLL Boston since late 2017. Additional residential development also would be part of the next phase, spokeswoman Andrea Simpson said.

The Rockville, Maryland-based REIT announced Thursday that 95 percent of the apartments at the 447-unit Montaje at Assembly Row are now leased, with an average rent of $3.40 per square foot.

The current phase of development also includes the 158-room Row Hotel which opened in August and 161,000 square feet of retail space, of which 117,000 square feet is now completed.