DENVER -- U.S. Postal Inspectors are warning residents that mail thieves are targeting apartment cluster mail boxes.

"There have been several cluster panel mailbox break-ins the past few weeks in the Denver metro area," said Postal Inspector Jeff Reed in a news release.

Reed said the break-ins have occurred at apartment cluster mailbox panel units and not at regular residential mailboxes, nor at centralized neighborhood cluster mailbox units, and not at blue collection boxes.

Officials said the best way to protect yourself is to pick up your mail in a timely manner and place a vacation hold on your mail if you are going away for any period of time.

"Postal Inspectors are concerned that thieves may be targeting mail in an attempt to obtain financial information," Reed said.

The U.S. Postal Service is offering a reward of up to $1,000 for information leading to the arrest and conviction of persons responsible for theft of mail. Postal Inspectors can be reached at 1-877-876-2455.