LAS VEGAS — The Monte Carlo resort has reopened three weeks after a rooftop fire.

Casino spokeswoman Yvette Monet says the Las Vegas Strip resort opened its casino floor and hotel at about 10:30 a.m. Friday following a pep rally for employees.

Resort-owner MGM Mirage Inc. estimates the Jan. 26 blaze cost about $100 million in repairs and lost business. County investigators believe the fire was caused by welders working on the roof.

The casino rushed to open about 1,200 of the hotel's 3,000-plus rooms in time for the three-day President's Day weekend. The hotel is fully staffed, Monet said.

An additional 1,300 rooms are due to open on Feb. 22. The last 500 rooms, mostly suites on the upper floors where damage was more extensive, will undergo complete renovations and will take longer to reopen.