MSN China, operator of e-communication services Messenger and Hotmail, said it has launched an investigation into account security after some users' accounts were found hacked and abused.

The statement was issued to Shanghai Daily yesterday after some locals complained that their accounts for the instant messaging and e-mail services have been cracked by hackers, who logged into their accounts to cheat their friends or relatives.

The hackers were found logging into the accounts, imitating the users by reading previous dialogue data, to send messages to their friends or relatives and lure them to click into virus-contained links, some victims said.

Some hackers would send messages to others, asking them to buy things for them, such as phone cards or online game cards, victims said.

Among the victims, a Shanghai woman, surnamed Wang, complained that she received a message from one of her friends last Friday via Messenger, who asked her to buy him prepaid phone cards and promised that he would pay her back the next day.

Wang spent 1,000 yuan (US$157) to purchase 10 cards for her "friend," sending him the cards' serial numbers and passwords, but the next day her "friend" never showed up again on Messenger.

When she called her friend, she was told that she must have been cheated by someone who hacked his account.

Another victim, a Shanghai man, surnamed Liu, complained that he clicked on one of the links sent by his friends and found his computer infected with a virus that hacked his own MSN account.

Anti-virus company Rising Co received 110 requests for help in a day over the scam.

Computer virus experts warned that a well-established grey industry chain was probably behind the incidents.

MSN China is investigating, and suggested users link their accounts with their cellphones to enhance security.