Boston’s office market had its slowest quarter in more than three years even before the brunt of COVID-19 impacts began to affect companies’ expansion strategies, according to a new research report.

The office market recorded 167,000 square feet of negative absorption in the first quarter, according to CBRE’s MarketView report. The vacancy rate rose 0.9 percent to 7.5 percent.

“As a result of the COVID-19 pandemic, significant challenges in the Boston office market lie ahead in the next few quarters – how much, how deep and how challenging remains to be seen as this unprecedented time continues to evolve,” the report states.

Despite the downturn, asking rents continued to climb and averaged $67.51 per square foot, up from $62.24 during the first quarter of 2019, and class A asking rents hit $72.78.

The largest new leases signed during the quarter were 68,000 square feet by the Boston Bruins/Delaware North Cos. and 34,000 square feet by the Boston Celtics, both at The Hub on Causeway office tower.

The Financial District had the biggest negative absorption at 215,000 square feet.

Subleasing activity contributed to an increase in the availability rate, which reached 13.9 percent, as State Street Corp. offered space at 100 Summer St. in the Financial District. Projected job cuts in the next two quarters is expected to contribute to a continuing uptick in sublease space, CBRE predicts.

But the COVID-19 impacts on office employment could be less severe than previous recessions, resulting in an “unusually swift recovery” beginning as soon as the third quarter, the report stated.