The NYPD is investigating after four portable batteries were found in the lobby of Trump Tower on Friday evening, two senior law enforcement officials tell News 4.

Officials say an all-clear was issued at President Trump's namesake skyscraper about 7 p.m. on Friday night, not long after a custodian first told officers about two unattended devices in the lobby.

Two additional devices were found during a broader search, and the NYPD bomb squad was called to investigate the scene.

A bomb dog sniffed the devices but did not sit. If the K-9 had, it would have indicated that the devices were dangerous.

The president's son, Eric Trump, tweeted that the items "turned out being USB chargers but always better to be safe than sorry."

Fifth Avenue was closed between East 56th and East 57th streets as the NYPD investigated, but it has since reopened.

It's not clear from where the items items came, for what they were being used or if they contained other instrumentation. It's also unknown if they were left behind by absentminded visitors or actors with ulterior motives.

Trump and first lady Melania Trump were both scheduled to be at the Trump National Golf Club Bedminster in New Jersey on Friday evening.

Sections of Trump Tower are open to the public, including its lobby and shops.

Public access has led to several scares involving items left by tourists, including a backpack containing toys that prompted an evacuation in 2016.