A former top executive of HSBC who told a United States senate hearing of his 'pain and embarrassment'' at the bank becoming a money-laundering conduit for drug cartels, rogue states and terrorist groups was born in Hong Kong and worked for the bank in the city for nearly 20 years. Christopher Lok Chiu-hon, who appeared before the US Senate Permanent Subcommittee on Investigations last Tuesday, joined the then Hongkong and Shanghai Banking Corporation in 1981. After a career spanning three decades - the bulk of which was spent in Hong Kong and Asia before he moved to the US in 2001 - Lok stepped down in 2009 as HSBC global head of banknotes after it became apparent that problems existed in the bank's anti-money-laundering procedures in the US. HSBC in Hong Kong declined to divulge any information about Lok's time with the bank in the city, citing 'privacy issues'. Spokesman Gareth Hewett said: 'We do not have anything to add to his testimony.' At the hearing in Washington, Lok opened his testimony by saying: 'I was born and raised in Hong Kong. In 1981, I started working in the banknotes business, and that's what I did for 29 years ... for most of my career I was based in Asia.' He went on to admit that, after moving to the US, at times he had dealt in an 'aggressive and harsh manner'' with colleagues in the bank's compliance section, which works to ensure that HSBC - one of the world's biggest banks - is not used by undesirable individuals, organisations or governments to launder money. 'Over a period of years, there were some occasions when I communicated with my colleagues in compliance in a manner that was unnecessarily aggressive and harsh. These communications were unprofessional, and I deeply regret them,'' he told the hearing chaired by Senator Carl Levin. 'For me, it is painful and embarrassing to talk about the areas where, in hindsight, we fell short,'' he added. A Senate investigation found lax controls at the bank allowed Mexican drug cartels to launder billions of dollars through its US operations. In addition, some HSBC bank affiliates skirted US government bans against financial transactions with Iran and other countries, according to the report. It also said HSBC's US division provided money and banking services to some banks in Saudi Arabia and Bangladesh believed to have helped fund al-Qaeda and other terrorist groups. HSBC's head of group compliance, David Bagley, stepped down at the hearing. The Senate report detailed individual cases such as that of Chinese-Mexican citizen Zhenli Ye Gon, a long-standing client of HBMX, HSBC's Mexican affiliate. In 2007, agents from the Mexican government and US Drug Enforcement Agency seized more than US$205 million in cash at his residence - described as the largest drug-related cash seizure in history. Earlier this year, Zhenli Ye Gon, whose notoriety earned him the nickname 'El Chino'' in Mexico, failed in a bid to unlock tens of millions of dollars from his alleged drug-trafficking fortune frozen in Hong Kong bank accounts. He is currently being held in a US jail. Lok told the hearing he thought the Mexican affiliate HBMX was operating on the same compliance standards as HSBC.