NEW DELHI (AFP) - India, known as the "pharmacy to the world", on Monday defended its lucrative generic drug industry as safe and strongly regulated after the nation's biggest drug firm pleaded guilty to US charges of making adulterated medicines.

In a bid to defend its generic export sector, the government also charged that "isolated reports" of spurious drugs found in global markets and alleged to be from India were "desperate attempts" by other countries hurt by "the strength of the Indian pharma industry".

India's "pharmaceutical sector is a highly regulated one and the exports are heavily guided by various regulatory regimes of the importing countries", the government said in a statement.

The statement came after New Delhi-based Ranbaxy Laboratories, India's largest drug company by sales, pleaded guilty in the United States to criminal charges of making adulterated medicines and agreed to a US$500 million (S$629 million) settlement.

The fraud, investigated over eight years by US authorities, was brought to light by a whistle-blowing ex-employee, who said Ranbaxy created "a complicated trail of falsified records and dangerous manufacturing practices".

India built a reputation as the "pharmacy to the world" for its production of life-saving generic versions of medicines for poor nations that cost a fraction of brand-name versions.

But analysts have warned that Indian drugmakers may find it tough to win new contracts in their main US market, with the case involving New Delhi-based Ranbaxy raising questions about the safety and quality of Indian-made drugs.

Generic drug firms in India have been a major supplier of copycat medicines to treat diseases such as cancer, TB and Aids for those who cannot afford expensive branded versions.

The country "has proven international quality standard capabilities", the government said.

It said India enjoys "a unique position of low-cost manufacturing and the highest quality medicine, the best of both the worlds".