Vandalism is seen Tuesday on the Lincoln Memorial. (Justin Wm. Moyer/The Washington Post)

A man was arrested Monday after police say he vandalized the Lincoln Memorial.

A U.S. Park Police officer observed the man about 1 p.m. using a penny to scrawl the letters "HYPT MAEK" on the fifth pillar on the north side of the memorial, authorities said.

The man, identified as 21-year-old Nurtilek Bakirov, of Kyrgyzstan, was arrested and charged with malicious destruction of property.

Sgt. Anna Rose, a Park Police spokeswoman, said during a news conference Tuesday that Bakirov was a student in the Washington area. Bakirov's attorney didn't return a request for comment.

Conservators are evaluating the damage to the monument to determine the best method for repairing it, police said.

It is unclear what the words mean, and they are difficult to see. The writing appeared to be Cyrillic and could include a reference to Bakirov's first name.

Documents filed in D.C. Superior Court indicate the letters "cannot be fully removed," but could be treated with polish in a process that would cost about $2,000.

Justine Bello, a architectural conservator for the National Park Service, said the vandalized area was small and the stone would weather out over time. When the Lincoln Memorial is vandalized, she said, staff decide how to respond on a case-by-case basis, testing treatments on a small area of the stone before proceeding.

"This is permanent damage," she said. "That is troubling."

The Lincoln Memorial, dedicated in 1922, was vandalized in August when someone defaced it with red paint. There's no indication that incident was related to this one, Rose said.

In another incident in February, someone wrote cryptic messages in black permanent marker on the memorial, the Washington Monument, the World War II Memorial and the D.C. War Memorial, including the words, "Jackie shot JFK."

In 2015, a case was dismissed against a Chinese woman who was suspected of tossing green paint on several D.C. landmarks, including the Lincoln Memorial, after a judge determined she was incompetent to stand trial.

Keith Alexander, Peter Hermann and Zofia Smardz contributed to this report.