Terracotta Warriors which guarded the tomb of China's First Emperor, Qin Shi Huang, on loan from China are displayed in The World Museum, Liverpool, Britain February 6, 2017. (Xinhua/REUTERS)

WASHINGTON, Feb. 23 (Xinhua) -- The Franklin Institute, a museum in the U.S. state of Pennsylvania, pledged on Friday to protect a set of China's terracotta warrior statues with the "utmost care and reverence," after a man stole a statue's thumb.

"The Franklin Institute has the utmost respect for the Terracotta Warriors and the rich Chinese cultural heritage they embody," the museum said in a statement obtained by Xinhua.

The statement came a week after authorities revealed that on Dec. 21, a man stole a thumb of a Chinese terracotta warrior statue exhibited at the institute.

The thumb was retrieved by the FBI and the suspect, identified as 24-year-old Michael Rohana from state of Delaware, was arrested and released on bail. He faces charges of theft of a major artwork from a museum and other offenses.

The 10 terracotta warrior statues at the Franklin Institute in Philadelphia were on loan from China for a special exhibition that began in September 2017 and will run until March 4.

The statues date back to at least 209 B.C. For more than 2,000 years, the life-size statues guarded the tomb of China's first emperor Qin Shi Huang, which covers an area of 56 sq km in Shaanxi Province in northwestern China.

While describing the theft as a "deplorable act," the institute said that it has been working with the FBI and other authorities to ensure that "justice for the individual responsible is served."

"We will continue to cooperate fully with our partners in China to maintain and protect the warriors with the utmost care and reverence," the statement said.

According to an arrest affidavit filed last week, Rohana was attending a party held at the Franklin Institute on Dec. 21 last year when he made his way into the museum's special exhibit "Terracotta Warriors of the First Emperor."

The FBI said that Rohana used a cellular telephone as a flashlight, looked at various exhibits displayed in the then-closed showroom, stepped up onto a platform supporting one of the statues, and took a selfie with it.

He put his hand on the left hand of the statue, appeared to break something off from the Calvaryman's left hand and put it in his pocket, and then left.

The Franklin Institute said on that night standard closing procedures were not followed by its external security contractor. It has reviewed its security protocol and procedures and taken appropriate action where needed.

"The Franklin Institute has multiple levels of security in place to ensure the safety of our artifacts, everything from personnel to technology that meets and exceeds museum industry standards," the museum said.

The incident has attracted great attention from both China and the United States amid calls for better protection of Chinese cultural artifacts on loan to other countries.

The cultural relics authority of China's Shaanxi Province said earlier this week that it will send two experts to repair the terracotta warrior statue.

The provincial cultural heritage department said that related U.S. departments should be held responsible for the damage, and guarantee the safety of the relics on display.

The Shaanxi Cultural Heritage Promotion Center has organized over 260 overseas exhibitions over the past 40 years, and has never come across a situation like this, said an official with the center.