A wildfire in Alaska's Kenai Peninsula has grown to cover more than 193 square miles.

Fire officials say the blaze was about 20 percent contained as of Sunday morning.

It threatens about 150 cabins, vacation homes and year-round residences in three communities.

Authorities have told people in those areas to be ready to leave, but had not issued an evacuation order.

The Funny River Fire burning in the 1.9-million-acre Kenai National Wildlife Refuge grew by about 42 square miles on Saturday.

About 409 firefighters are assigned to the fire, which is the most active of several large wildfires burning in Alaska.