MUMBAI, India — The Indian government said Thursday that it would block encrypted BlackBerry corporate e-mail and Messenger services if wireless companies did not enable law enforcement authorities to monitor those messages by the end of the month.

The ultimatum suggested that Indian officials had reached an impasse after weeks of negotiations with Research In Motion, the Canadian company that makes and provides services for the popular hand-held devices. India would become the second country in recent weeks to restrict BlackBerry services. The United Arab Emirates announced last week that it would begin blocking services in October.

“If a technical solution is not provided by 31st August, 2010, the government will review the position and take steps to block these two services from the network,” the Home Ministry, the Indian equivalent of the U.S. Justice Department, said in a statement.