The painting, one of Rotko's acclaimed Seagram murals, was daubed with black marker pen
on the afternoon of Sunday October 7 (at around 3.35 p.m., GMT).
Once the act of vandalism was spotted, the gallery was shut for a short period and then reopened and the police were called to investigate the incident, according to the BBC.
A spokesperson for the Tate Modern is reported by the Daily Express
as saying: "Tate can confirm that at 3.25pm this afternoon, there was an incident at Tate Modern in which a visitor defaced one of Rothko's Seagram murals by applying a small area of black paint with a brush to the painting. The police are currently investigating the incident."
was a Russian born painter. He became a U.S. citizen and was one of the pioneers of abstract painting.
With the Seagram murals
, Rothko was commissioned to paint the pictures in 1958 for Manhattan's Four Seasons restaurant. However, the artist then changed his mind about exhibiting the works and just prior to before his death in 1970, Rothko presented some of the murals to the Tate Gallery in London.
The Tate, one of the world's most renowned modern art galleries, created its dedicated Rothko room in to house the Seagram collection.