The income tax department has seized shares of Unitech Group companies through which the realty firm holds stake in mobile telecom company Uninor.

?We can confirm that Uninor is in receipt of notices from the I-T department stating that the shares owned by Unitech, through their companies Acorus, Cestos and Simpson, in our company have been attached,? Uninor said on Wednesday. It said its group firms have challenged the order saying the demand was based on the ?presumptive gains? on their shareholding in Unitech Wireless.