The Palace Museum has unveiled plans to better preserve Beijing's top tourist attraction by introducing nightly armed police patrols and strictly enforcing a complex-wide smoking ban.

A smoking ban has long existed at the museum, also known as the Forbidden City, although it has rarely been enforced.

Zhang Ying, a media officer from the museum, told the Global Times that the measures aim to better protect the 170,000-square-meter ancient site that is home to nearly 2 million cultural relics.

"The smoking ban applies to everyone, including tourists and staff. Everyone will have to go outside the museum's grounds if they wish to smoke in the future," said Zhang, without specifying what punishment awaits those caught lighting up where they shouldn't.

"In the past, we had no real authority to punish smokers. All we could do was warn them if caught."

Shan Jixiang, curator of the museum, told the Beijing Times nobody would be exempt from the ban in the future, acknowledging some museum staff in the past had flaunted the regulation.

"We can't ask visitors not to smoke while our employees smoke in their offices," Shan said.

The Palace Museum will also strengthen its security by introducing armed-police night patrols, the Beijing Times reported, although no date has been set for the start of the patrols.

The museum's lax security was exposed in May 2011 when a man stole several imperial relics worth millions of dollars after breaking into the complex through the wall. The thief, a 27-year-old farmer from Shandong Province, was later arrested and jailed for 13 years by a Beijing court.  

In the wake of the robbery, the Xinhua News Agency reported the museum would upgrade its alarms to prevent such thefts in the future.

The Ministry of Public Security approved the armed-police patrols at the museum's request. Shan said the armed police would bolster the museum's current 100-strong security guard force.

Cui Jinze, a member of the Chinese Commission for the International Council on Monuments and Sites, welcomed the new measures, saying they would ensure future generations could appreciate treasures at the site that was home to emperors for almost 600 years.

"Smoking must be banned. Many fires that have destroyed cultural relics in China over the past six decades have been sparked by cigarettes. Most ancient buildings are wooden, highlighting the need for smoking bans," Cui said.