May 28 (Reuters) - Authorities in southwestern Arkansas have launched a manhunt for two murder suspects who escaped from jail before dawn on Monday by cutting through the window bars of their second-story cell with a hacksaw, sheriff's officials said.

After removing the bars and smashing through a pane of glass, the two men then shoved mattresses through the window and climbed out of the Miller County Sheriff's Detention Center in Texarkana, Arkansas, spokeswoman Vanessa Schaeffer said.

"They pushed through mattresses to soften their drop to the ground," Schaeffer said.

The pair then cleared a 10-foot-high fence topped with razor wire before disappearing beyond the confines of the facility, she said.

Authorities brought in a K-9 dog unit to search the area after jail staff discovered the breakout at about 4 a.m. but failed to locate the two men in the immediate vicinity.

The fugitives were identified as Cortez Rashod Hooper, 23, and Quincy Vernard Stewart, 36, both described as dangerous. Schaeffer said the search for the pair was continuing and that members of the public who might encounter them were advised to keep their distance and call 911.

"Don't approach them," Schaeffer said.

Officials declined to say how the pair obtained a hacksaw in their jail cell or whether the tool was recovered.

Hooper, who stands 5-foot-4 and weighs 130 pounds, is charged with first-degree murder, aggravated assault and a probation violation.

Stewart, who is 5 foot-7 and weighs 169 pounds, is charged with possessing a controlled substance and was to be turned over to authorities in neighboring Bowie County, Texas, on suspicion of capital murder. (Reporting by Barbara Goldberg; Editing by Steve Gorman and Philip Barbara)