OSAKA -- Major drugmaker Rohto Pharmaceutical disclosed Wednesday that it has received letters claiming its eyedrops would be tampered with unless it pays 100 million yen in cash.

According to company officials, the letters said Rohto eyedrops mixed with a foreign substance would be placed on store shelves unless the money was paid.

However, the firm said it had no plans to remove its products from store shelves, citing the fact that they could not be tampered with without opening the inner package.