A downtown office tower owned by the city of Los Angeles was so badly damaged by a massive fire at a construction site this week that it will likely stay shut for up to six months, city representatives said Tuesday.

More than 300 windows were blown out at 221 Figueroa St. after a fire tore through the nearby Da Vinci apartment complex early Monday morning.

Repair costs to the city-owned tower will be tens of millions of dollars, officials said, adding that the site is insured.

The building needs extensive renovations, officials said, citing heat and water damage. The blaze melted computers, shattered windows and damaged carpets.

Hundreds of employees have been relocated to other city facilities.

“It’s not a safe place to put people in,” said Tony Royster, head of city’s General Services department during a City Hall hearing Tuesday on the fire.

Officials are investigating the blaze that destroyed a large, under-construction apartment complex owned by developer Geoffrey Palmer.

The Bureau of Alcohol, Tobacco, Firearms and Explosives and local arson officials are on site, officials said.

The 221 Figueroa office tower houses police and fire personnel, as well as workers for the Department of Recreation and Parks, Animal Services and other city departments.

Some non-city tenants also work in the building, officials said.

In additional to structural damage, up to 500 city-owned computers may have to be replaced, at a cost of up to $500,000, said Steve Reneker, head of the city’s technology department.

The blaze also damaged another city-owned property at 201 Figueroa St. It suffered minimal damage and is expected to open later in the week.

Pat Huber, an assistant city administrative officer, said the two towers are insured for up to $1 billion. The city’s deductible is $100,000, Huber said.

Los Angeles Fire Department Assistant Chief Patrick Butler said the exposed buildings are a concern because of a storm expected to hit the city later this week.

“We’re preparing for a large storm on Thursday and Friday with 50-mile-an-hour winds,” Butler said. “So another effort will be, how do we protect those open spaces on those buildings?”