HONG KONG (AFP) - A member of a Hong Kong pro-democracy party claimed Friday (Aug 11) he was abducted and beaten by mainland agents after saying he wanted to send a signed photo of footballer Lionel Messi to the wife of late Chinese dissident Liu Xiaobo.

Howard Lam held an explosive press conference Friday, showing his legs punctured by metal staples and red marks on his stomach.

He was in hospital Friday afternoon and had reported the incident to police, said the Democratic Party to which he belonged.

It is illegal for mainland agents to operate in semi-autonomous Hong Kong, but the alleged abductions of a city bookseller and a reclusive mainland businessman have put the city on edge.

While Hong Kong still enjoys rights and freedoms unseen on the mainland, there are growing concerns over increased Chinese interference.

Lam said he was abducted Thursday by Mandarin-speaking men. The official language in Hong Kong is Cantonese, while Mandarin is the main language over the border.

Lam said he had received a phone call Tuesday from a man who claimed to speak for Chinese authorities telling him not to send a picture of Messi to the widow of Nobel Peace Prize laureate Liu Xiaobo - who died in Chinese custody from liver cancer last month, sparking global outrage.

Lam had previously said on Facebook that the Barcelona star had sent him the photo for Liu, who was reportedly a fan.

As it arrived after Liu's death, Lam had said he would try sending it to his wife Liu Xia.

She has not been in touch with anyone since about a day before her husband's death, her lawyer has said. He has filed a complaint to the United Nations accusing the Chinese government of her "enforced disappearance".

Lam said he had been forced into a van Thursday afternoon while shopping in the busy commercial area of Mong Kok.

"Once in the van, there was a struggle, I started to shout, and then they hit me in the temple," Lam said, adding the men made him smell something which caused him to fall unconscious.

He later woke up to more beating and was asked if he knew Liu Xia.

Lam said the men punched staples in his thighs and asked him whether he understood how to "love the country".

They identified him as a Christian and told him that as a religious man he should be obedient.

One man said he would "give him crosses" and punched the staples into his legs in cross-shaped patterns.

"It was very painful, I yelled out," Lam recalled, showing around 20 staples still in his thighs.

He again fell unconscious after being forced to smell a substance and found himself by a beach in the remote Sai Kung district in the small hours of Friday.

Democratic Party lawmaker Lam Cheuk Ting said the party believed those who carried out the abduction were mainland agents.

"I am astonished," he told AFP, saying it violated the city's semi-autonomous "one country, two systems" set-up.

"It happens again and again."