Users of RIM's BlackBerry devices were cut off from their email services last night.

The shutdown occurred at around 8pm EST and service was not resumed until late into the night for most users. RIM has given no reason for the shutdown but said that European users were not affected.

"A service interruption occurred on Tuesday night that affected BlackBerry in North America. Email delivery was delayed or intermittent during the service interruption," said a company spokeswoman.

"Phone service on BlackBerry handsets was unaffected. Root cause is currently under review, but service for most customers was restored overnight and RIM is closely monitoring systems in order to maintain normal service levels."

The company is now monitoring systems to make sure that the system is not overloaded as people try and catch up on their emails.