By Jim Forsyth

SAN ANTONIO (Reuters) - An El Paso man faces up to 18 months in jail after pleading guilty to urinating on the Alamo, the iconic structure seen by many as the symbol of the Texas spirit.

"The message is, 'don't whiz on the Alamo,'" Bexar County District Attorney Susan Reed, said in a statement that added she would oppose any request for probation.

Daniel Athens, 23, pleaded guilty in a San Antonio court on Tuesday to the felony of Criminal Mischief of a Public Monument or Place of Human Burial, which carries a punishment of up to two years in prison.

Lawyers for Athens are working on a plea bargain with prosecutors, who are seeking 18 months in prison and drawing a line in the sand for a sentence that includes jail time.

Athens was arrested in April 2012 after an Alamo Ranger, one of the police officers who guard the state's No. 1 tourist attraction, saw him relieve himself on the 260-year-old limestone facade of the building.

As part of a plea deal, Athens will have to pay $4,000 to repair any damage he caused.

The Alamo was constructed in the 1750s by Spanish colonists as a chapel to bring Christianity to the native peoples of what is now Texas.

It is best known for the 1836 battle between the Mexican Army and Texas settlers fighting for independence from Mexico.

The Alamo has suffered its share of urinary insults over the years, the most famous was from British rocker Ozzy Osbourne, who in 1982 urinated on the Cenotaph, a memorial to the Texans killed at the battle.

Osbourne was banned from the city by the city council, a symbolic move that was later rescinded after he donated $10,000 for the Alamo's upkeep.

(Reporting by Jim Forsyth in San Antonio; Writing by Jon Herskovitz; Editing by Steve Orlofsky)