Two separate fires at a Madison Avenue office building early yesterday morning left seven firefighters with minor injuries.

Fire officials said they were investigating a three-alarm blaze that began at about 1:15 a.m. and a separate fire that began at about 3:45 a.m. inside the Art Deco highrise office building at 295 Madison Ave. near East 41st Street.

The firefighters were treated at Columbia Presbyterian Hospital and released, fire officials said.

The 47-story commercial building reportedly sold for $180 million to real estate mogul Joseph Moinian, the chief executive officer of the Moinian Group, in a quiet deal that closed last month, according to news reports. Several staffing agencies and law firms have space in the building.

Fire officials said yesterday that while the first fire, on the 12th floor, was put out quickly, it was not declared under control until about four hours later, at 4:32 a.m. The second fire, on the 16th floor, started as firefighters were dealing with the first one, but officials said firefighters were able to tamp it down much more quickly than the initial fire.

Fire officials would not comment yesterday on whether they viewed the fires as suspicious, saying the investigation was ongoing. Investigators and tenants filed in and out of the building yesterday, assessing damages. Tenants said they had observed extensive damage to some offices on the 12th floor and minimal damage on the 16th floor.

The building is two blocks from the spot where an underground steam pipe exploded this month. The Moinian Group has been working closely with the fire department, a spokeswoman for the company, Daphne Viders, said. They plan to wait on the results of the investigation, she added.