Springtime in Manhattan was far from sunny for home sellers, as inventory increased, prices continued to decline and sales volume dropped to its lowest level in nine years, according to new market reports.

Real estate agents pointed to rising mortgage interest rates and uncertainty surrounding the federal tax overhaul that went into effect late last year. The result was a widening gap between buyers and sellers, who often hit an impasse on price.

There were 2,629 closed sales in the second quarter — a nearly 17 percent drop from the same period last year, according to a new Douglas Elliman report. That is the lowest number of spring sales since 2009, when the market was stifled by the recession, said Jonathan J. Miller, the real estate appraiser who prepared the report.

Overall, the median Manhattan sales price in the quarter fell to $1.1 million, down 7.5 percent from the same quarter last year. Part of that decline reflected a shift away from pricier new-development sales. There were just 352 new apartment sales in the quarter, down almost 37 percent from the same quarter last year, Mr. Miller said, and the units that did sell were less expensive.