Amazon is in “advanced discussions” with Virginia officials about selecting the Crystal City site in Arlington County as its second headquarters, the Washington Post reports.

The talks have included specifics on the number of buildings and timing of employees moving to the site, which could eventually host up to 50,000 jobs, the newspaper reported.

The Washington, D.C. area was the only metro region with three semi-finalists after Amazon narrowed its list of options from 238 to 20 in January. An announcement is expected by year’s end.

Boston Mayor Marty Walsh and Revere Mayor Brian Arrigo presented the 161-acre Suffolk Downs racetrack property in East Boston and Revere as the region’s top landing spot for Amazon. Boston-based HYM Investment Group, which bought the property in 2017 for $155 million in 2017, has proposed 16.5 million square feet of development on the site. Seattle-based Amazon said it needs eight million square feet of office space for a second headquarters.

Somerville Mayor Joseph Curtatone separately proposed a group of properties along the MBTA Orange Line corridor from Boston to Somerville.

The largest developer in Crystal City, JBG Smith, has pulled some of its buildings off the market and an announcement is planned following the midterm elections, the Post reported. It was unclear whether Amazon was engaged in the same level of negotiations with other semi-finalists.

A survey of more than 100 housing and economic experts by Zillow earlier this year listed the Virginia site and Atlanta as the two likely front-runners for HQ2. An educated workforce and strong public transit favored the Virginia bid, Zillow said.

Amazon already has tech offices in Cambridge and 253 Summer St. in Boston and plans to hire 2,000 employees for a 430,000-square-foot office building scheduled to open in 2021 in the Seaport District.