More than 1,300 hotel rooms would be built in Boston’s Seaport District on parcels owned by Massport under two projects that moved forward this week.

Boston Planning and Development Agency directors approved a 1,000-key hotel on Summer Street designed to provide meeting planners with a new supply of rooms directly across from the Boston Convention and Exhibition Center.

Earlier, Hyatt Hotel Corp. and McWhinney Real Estate services signed a ground lease for a 293-room hotel on Massport’s 2.4-acre parcel K on at 315 Northern Ave.

Scheduled to be completed in 2021, the $500-million Summer Street hotel will include more than 100,000 square feet of meeting and event space, the largest block yet to be built in the Seaport, developers said. Two 21-story towers will house more than 1,000 rooms. The property will connect to the convention center with a covered pedestrian bridge and a tunnel under Summer Street.

In April, Massport selected a consortium of developers including Omni Hotels & Resorts and Boston-based Davis Cos. to build the project.