BlackBerry maker Research In Motion Ltd, which is losing share of the corporate email market it once took for granted, said it was working on the problem but gave no details of the cause.
"Some users in Europe, the Middle East and Africa (EMEA), India, Brazil, Chile, and Argentina are experiencing messaging and browsing delays. We are working to restore normal service as quickly as possible," it said in a statement.
"We apologize for any inconvenience this has caused," said RIM, which earlier on Tuesday said it had resolved problems disrupting its services in EMEA.
RIM is already facing calls from some investors for a break-up, sale or change of management following dismal recent results and a lackluster reception of its PlayBook tablet computer, designed to challenge Apple Inc's iPad.
Its previous dominance of the corporate email market, in which it locked organizations into its proprietary, secure servers, is being challenged by other smartphone makers led by the Apple iPhone.
"The current situation with the BlackBerry outages couldn't come at a worse time for RIM, following some harsh criticism in recent months," Informa Telecoms & Media analyst Malik Saadi said in a statement.
"Some businesses may see this as a good reason to re-evaluate their reliance on centralized servers and instead look to investing in more corporately controlled servers.
"Not only would this enable IT departments to minimize the risk of unforeseen collapses, but it could also give employees more flexibility to use their own devices."
Network operators and users in EMEA tweeted that email and BlackBerry Messenger services were not working from around 1100 GMT. Reuters correspondents also reported problems with email and instant messenger services.
Network operator T-Mobile said on its website that the problems were due to a European-wide outage on the Blackberry network.
It said: "RIM has apologized for the interruption to services and said it's working to restore normal operations."
Earlier, RIM said it had restored BlackBerry services in the region, some 20 hours after users in EMEA and India first reported problems with email and BlackBerry Messenger.