Tens of thousands of police officers and dozens of top law enforcement officials — including U.S. Attorney General Jeff Sessions — will convene in Center City over the next several days for one of the largest annual police conferences in the world, a major event among cops that also is expected to attract scores of protesters.

The event, which kicks off Saturday and is hosted by the International Association of Chiefs of Police, comes at a tumultuous time for law enforcement. The Trump administration and Sessions have been putting a "law and order" stamp on policies affecting local policing, even as many criminal justice leaders and elected officials — including in Philadelphia — have begun focusing on progressive-style reforms.

The conference has no overarching theme, and panel discussions range from the obvious (addressing gun violence), to the unexpected (preventing heart attacks among police officers).

Sessions is expected to deliver a speech Saturday, according to association spokeswoman Sarah Guy.

One panel, titled "The New Face of Fraud and Its Possible Nexus to Terrorism," is hosted by Jonathan Josey, a Philadelphia police lieutenant who earned notoriety in 2012 after a video posted on social media showed him striking a woman at a parade. (Josey was fired and criminally charged but was acquitted and rehired.)

Michael Chitwood, superintendent of Upper Darby Police, said the conference "encompasses everything."

"It encompasses technology, it encompasses Supreme Court [decisions], it encompasses best police practices," he said. "You're going to take away from it what you put into it."

Despite having nearly 200 pages of descriptions online about the various panel discussions, almost none of the sessions was expected to be open to the public or press. A media policy posted online said reporters would be limited to a few major sessions, and "unscheduled" interviews with the conference's estimated 14,000 attendees were barred.

Guy did not provide an explanation, nor did the policy itself. Melissa Melewsky, media law counsel at the Pennsylvania NewsMedia Association, said the organization could set its own access rules because it is a private group.

Local police are preparing for protests. Several hundred people expressed interest in a weekend demonstration being promoted on Facebook, although it was not clear how many would attend. Sixty-six protesters were arrested outside the conference in Chicago in 2015.

Philadelphia has earned plaudits for how police have handled protesters at other recent big events, such as the pope's visit and the Democratic National Convention, but it is still perhaps a unique host city for this particular event.

The city has been battling Sessions' Department of Justice over whether it can legally remain a "sanctuary city," and the District Attorney's Office soon may be headed by Larry Krasner, a lifelong defense attorney whose campaign has centered on eliminating so-called mass incarceration and ending use of the death penalty.

Police Commissioner Richard Ross said he looked forward to interacting with police leaders and learning about new technologies, policies, and approaches.

Thomas Nestel, chief of SEPTA police, described the conference as "continuing education for cops."

"I'm going to walk over there to try and listen and learn in a number of the sessions," he said. "I think it's a great opportunity."