After three days of disruptions, BlackBerry services offering e-mail, messenger and other online services were restored, Canada-based Research in Motion said.

"Email systems are operating and we are continuing to clear any backlogged messages. Support teams are working to minimise the impact on our customers... We are working to restore normal service levels in all markets as quickly as we can," Research In Motion (RIM), maker of BlackBerry, Chief Information Officer Robin Bienfait said.

Since Monday, scores of BlackBerry users in Europe, the Middle East, India and Africa (EMEIA), Canada, Latin America and US were facing problems in accessing the e-mail, messenger and other online services on their smartphones caused by a core switch failure.

RIM has about a million subscribers of BlackBerry services in India.

However, there was no clarity among the operators on the issue of offering any rebate on the tariff packages during the last three days as the service remained disrupted.

"I want to first apologise for the service interruptions and delays many of you have been experiencing this week... We are doing everything in our power to restore regular service everywhere and to restore your trust in us," Bienfait said in his message posted on the company's website.