Major networks are joining forces to craft demands about access to Donald Trump’s campaign. (EPA/Erik S. Lesser)

Network TV news representatives will confer Monday to hash out demands about access to Donald Trump’s presidential campaign after Trump officials last week threatened to “blacklist” reporters who left a designated media “pen” during rallies for the presidential front-runner.

According to people at multiple networks, senior managers from the five leading TV news networks — ABC News, CBS News, CNN, Fox and NBC News — will discuss their response in an effort to push back against what they deem harsh and restrictive behavior by Trump’s managers, including his top aide, campaign manager Corey Lewandowski.

Lewandowski threatened to pull the press credentials of a CNN reporter, Noah Gray, last week after Gray sought to leave the press pen during a Trump campaign appearance in Worcester, Mass. Gray, an “embed” for the network who has covered Trump for months, recorded Lewandowski’s threat to “blacklist” him and posted it online.

Reporters clashed again with Lewandowski and Trump press secretary Hope Hicks on Friday at an event in Spartanburg, S.C. When the journalists tried to interview voters before Trump’s speech, they were ordered to return to the press pen, under threat of losing their credentials. They later defied an order by Hicks to remain in the press area, a small area bordered by bicycle rack-like barriers, while Trump greeted supporters on a rope line afterward.

For many years, candidates and elected officials have restricted reporters to a press zone during public events. The nominal reasons are safety and security, and to avoid disruptions that may occur during a speech if a camera crew were to jostle its way through a crowd.

But Trump’s campaign has enforced even tighter restrictions than is typical, such as ordering media people to stay in the pen before events. Some reporters covering Trump suspect the campaign is clamping down on their movements to block them from recording protests by activists and others during his appearances.

Hicks did not return an e-mail or phone call seeking comment on Sunday.

Trump’s campaign has had unusually testy relations with the press corps. Campaign reporters who have crossed Lewandowski say he has retaliated by temporarily blacklisting them, assigning them to what he has termed “the doghouse.”

The campaign has also declined to give credentials to reporters from news organizations it has deemed unfriendly. The list includes BuzzFeed, the Huffington Post, Fusion, Univision and the Des Moines Register, the largest paper in the state holding the nation’s first caucus. The latter says it has been kept out of Trump’s events as a result of an editorial the paper published in July urging Trump to withdraw from the race.

By presenting a unified front, the five networks involved in Monday’s discussion will have greater leverage with the campaign than any individual organization. The networks remain the most popular conduit through which voters get information about the campaign.

The networks on Monday will attempt to draft a common response to Trump’s managers during a conference call. The group wants to seek an agreement with the campaign about how the press pen will be managed, instead of the campaign dictating its terms, according to people knowledgeable about the discussion.

They also want campaign officials to stop issuing threats to pull credentials or bar network journalists.