HONG KONG (Reuters) - For the thousands of Chinese soldiers stationed in Hong Kong, the pen, it appears, is mightier than the sword.

Pens, contraceptives, lipstick, eye drops, opium, perfume and pets were among an unlikely list of items guests were banned from taking on a trip to a People’s Liberation Army (PLA) base on Friday as part of activities to mark the 20th anniversary of Hong Kong’s handover from British to Chinese rule.

Security officers were taking no chances as they offered invitation-only guests a rare glimpse of barracks life at the Shek Kong base in a lush corner of the New Territories that sits in the shadow of Tai Mo Shan, Hong Kong’s highest mountain.

Umbrellas, a symbol of pro-democracy protests in 2014, were also banned but purple alternatives were provided.

The roughly 1,500 guests were told to pull down their souvenir umbrellas, even as temperatures sweltered above 30 degrees Celsius (86 degrees Fahrenheit), when Chinese President Xi Jinping arrived to inspect a military parade.

Security personnel also confiscated a pen, taxi receipts, a 4G dongle, water, mints and pain relief tablets and other medication from Reuters reporters. Several correspondents had their notebooks searched.

A list of prohibited items provided to reporters ahead of the visit also included heroin, marijuana, psychotropic substances, sunscreen, cosmetics, microwave transmission equipment, animals and plants.

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Police were stationed on top of roadside cliffs leading to the base as helicopters circled overhead.

Guests were treated to a military display that included Z8 helicopters, mobile air defense missile trucks and armored cars as martial music drowned out the high-pitched song of cicadas.

PLA soldiers also handed guests goody bags filled with camouflage hats, flags, water, biscuits, and a bun.

Xi, who oversees the PLA in his role as head of the powerful Central Military Commission, arrived in a motorcade and inspected 20 squadrons of troops and more then 100 pieces of military equipment, as music blasted from loud speakers.

While its precise numbers are unknown, foreign envoys and diplomats believe the PLA garrison in Hong Kong is made up of between 8,000-10,000 personnel, including infantry and special forces troops.

The force is split between a network of barracks and facilities inherited from the British military in Hong Kong, as well as bases across the border in Guangdong, where its jet fighter planes are kept.

The troops spend their time isolated on barracks strictly separated from the public.