Singapore: Days after China concluded its probe against British drug maker GlaxoSmithKline and charged certain executives of the company with corruption - more troubles have emerged for the company.

Britain's Serious Fraud Office (SFO) has now launched a formal criminal investigation against the company that is currently also facing similar allegations in four other counties.

The SFO said that its director had "opened a criminal investigation into the commercial practices of GlaxoSmithKline and its subsidiaries", confirming an earlier brief statement from the company.

"GSK is committed to operating its business to the highest ethical standards and will continue to cooperate fully with the SFO," a statement by the company read.

On May 14, the Chinese police said that they had charged the former British head of GSK's China business and other colleagues with corruption, after an investigation there found evidence of an elaborate scheme to bribe doctors and hospitals. This case is said to be the biggest corruption scandal to hit a foreign company in China since the Rio Tinto affair in 2009, which resulted in four executives, including an Australian, being jailed, reports illustrated.

Experts had earlier made an indication that GSK cover face charges under the UK Bribery Act. As per the act, companies are prohibited from making payments to government officials, including state-employed doctors, to obtain business overseas.

GSK is now also investigating bribery claims in Poland, Iraq, Jordan and Lebanon.