George Flannigan, spokesman for post offices in the Erie district, said each postmaster or station manager gave a "stand-up talk to all employees" Saturday morning and again today about being careful.

Mercer County is in the Erie district.

"A (memo) was issued to all of the post offices Saturday morning cautioning carriers to be on the look out for anything suspicious."

"At this time, we're not asking residents to leave their mailboxes open. The incidents that happened were in the Midwest. There hasn't been anything occurring around here."

Flannigan said carriers were cautioned about anything protruding from the box or any open mailboxes that look unusual or suspicious.

In Brookfield, residents are going to be issued precautionary measures later today, said Postmaster Randy Monfredi.

"We haven't been able to ask residents to leave their boxes open, but a national precaution is being announced today," Monfredi said.

As for mail carriers, they are being asked to "be careful," he said.

"We're just going to ask carriers to be extremely cautious. We're telling them don't just put your hand in the mailbox until you're sure it's safe. There's not much else (precautions) to do."