(CNN) -- Firefighters battling a California wildfire overnight progressed in making containment lines, though the fire's overall containment remained steady.
The firefighters took advantage of the lower temperatures at night to make "backfires" that helped secure the containment lines, fire management spokesman Marc Peebles said.
The Friday night work, however, did not change the percentage of the fire that was contained. It remained at 30%.
The Colby wildfire, as it is called, continued to burn Saturday on about 1,863 acres of foothills of Los Angeles County near Glendora. An illegal campfire apparently ignited the wildfire, and fire officials cited drought conditions as contributing to the blaze.
A day earlier, California Gov. Jerry Brown declared a drought emergency for the state, saying it is facing "perhaps the worst drought that California has ever seen since records (began) about 100 years ago."
The Colby fire began before dawn Thursday and allegedly originated with three men camping in the foothills near Glendora, authorities said. The campers were tossing paper into a campfire, and a gust of wind spread embers, authorities said.
The three men, all in their early 20s, were arrested on suspicion of recklessly starting a fire, said police Chief Tim Staab of Glendora. One man is from Glendora and another is from Irwindale, he said. The third man's hometown was not known. Bail was set Thursday at $20,000 for each.
The three men arrested were identified as Jonathan Carl Jerrell, 23; Clifford Eugene Henry Jr., 22; and Steven Robert Aguirre, 21, police said. They and their attorneys couldn't be reached for comment.