BOSTON (AP) — Boston and neighboring Somerville remained in contention Thursday to serve as host city for Amazon's second North American headquarters, but a number of other prospective sites in Massachusetts were eliminated.

Amazon included Boston on a list of 20 finalists for the $5 billion project that the e-commerce giant says will generate up to 50,000 new jobs.

A company spokesman later clarified it was referring to the metropolitan Boston area and that proposals from both the city of Boston itself and from Somerville would move on to the next phase of the selection process.

"As a thriving city with a talented and diverse workforce, culture of innovation and opportunity for all, I see no better city ... for Amazon to call their second home," Boston Mayor Marty Walsh said in a statement.

John Barros, Boston's chief of economic development, said city officials still consider Suffolk Downs, a former race track near Logan International Airport, to be the location that best aligns with Amazon's stated preferences. But he added the city was open to other potential sites as well.

Somerville's proposal did not name a specific site but rather what it called a "regional solution," one which would incorporate development sites along the MBTA's Orange Line and soon-to-be-expanded Green Line.

Republican Gov. Charlie Baker's administration submitted 26 prospective locations, including Somerville and four different sites in Boston.

"This is a great statement about the quality of life, about the quality of the workforce, the quality of the people and the institutions that make up Massachusetts," Baker said of Amazon's announcement Thursday. He told reporters it was too early to speculate on any proposals his administration might offer during the next round of discussions with the Seattle-based company.

The state has not dangled any specific tax breaks or other financial incentives before Amazon, but has touted existing state programs that offer tax credits and infrastructure investment to spur economic development and job growth.

Worcester, New Bedford and Lawrence were among other Massachusetts cities that also made proposals but were not among the finalists.

George Proakis, Somerville's director of planning, said his city's proposal was focused less on creating a single campus for Amazon, but instead emphasizing "smart growth" development and proximity to several prestigious universities.

"We wanted them to consider Somerville based on who we are and what we are, our diversity and our knowledge-based workforce," Proakis said.

Boston's bid for Amazon referenced the city's efforts to increase the supply of affordable housing, provide workforce training and improve transportation.

"Whether it's the MBTA, or roads and bridges, we think infrastructure and infrastructure investments are critical," Barros said.

The city might also weigh property tax breaks of the type provided to General Electric when that company moved its corporate headquarters to Boston in 2016, he added.