Alarmed by an upsurge in gang-related graffiti along Prince Memorial Greenway, Santa Rosa police staked out an area recently painted over by city crews and arrested two young men suspected of vandalizing the area.

The bulk of the offending graffiti had been scrawled along a 600-foot stretch of wall between Santa Rosa Avenue and Railroad Street, where new gang epithets and threats appeared May 23, fueling counter vandalism, police said.

City crews painted over the markings early Wednesday, and police then put the area under surveillance Wednesday night.

Officers were watching around 11:30 p.m. Wednesday when they saw two men spray-painting new graffiti onto the walls, authorities said.

Police arrested Joseph R. Spratling, 21, and Felix Fernando Carreon III, 18, for suspected vandalism with a gang enhancement that would earn them stiffer penalties with a conviction.

The two men were booked into the Sonoma County Jail on Thursday, with bail of $15,000 each, jail personnel said.