Hong Kong protesters have urged customers of HSBC Holdings PLC to boycott the U.K.-headquartered lender for allegedly helping the police shut down a major funding source for them, the Financial Times reported.

Hong Kong's police froze HK$70 million of assets held by the Spark Alliance fund on Dec. 19 and arrested four people over alleged money laundering, the report said. The fund, which raised money to provide aid to anti-government protesters, received HK$80 million of donations primarily through an HSBC account closed last month, the FT said, citing police officials. The police also said the individuals used part of the money to purchase personal insurance products, according to the report.

A spokesman for the bank, however, said the decision to close the account was "completely unrelated" to the arrests, the FT said. HSBC also said in a Facebook post that the account's owner failed to properly explain unusual activity in the account.

"During the past few months in working with the customer these requirements were not met and therefore we closed their account," HSBC said.

HSBC is the primary lender in Hong Kong, with the bank and sister company Hang Seng Bank Ltd. dominating 40% of the financial hub's retail banking sector, the FT noted.