WASHINGTON – The U.S. Postal Service lost $1.3 billion in the final three months of last year despite a blizzard of campaign advertising for the fall political elections and a big holiday mail and shipping season.

The loss announced Friday was far less than the $3.3 billion in the comparable quarter the previous fiscal year, but still showed the effects of a continued decline in first-class mailing as customers continue to flock to the Internet for emailing, bill paying and the like.

In releasing their financial report, postal officials pleaded anew with Congress to give them the flexibility to better manage the agency — including to free it from a mandate that they prepay for expected retiree health care costs.