The feud between Hillary Clinton’s presidential campaign and the news media escalated on Monday, when the reporter designated by the traveling press to cover Clinton’s events here was denied access.

David Martosko, the US political editor at the Daily Mail, was scheduled as the so-called “pool” reporter for Clinton’s visit through New Hampshire. But when he arrived at the gathering spot for the traveling press corps on Monday morning, Martosko was turned away by a Clinton staffer who said the reporter was no longer the approved pooler for the day’s events.

Clinton spokesman Nick Merrill later offered what Martosko called “varied and contradictory” reasons for not allowing him to join the pool – a rotating group of news outlets that represent the entire press corps and put together reports on the president and presidential candidates that are then distributed to members of the media.

“We’ve been getting a lot of blowback from foreign outlets that want to be part of the pool and we need to rethink it all, maybe for a day, and just cool things off until we can have a discussion,” Merrill said, according to Martosko’s pool report.

Martosko said he pointed out that other foreign outlets are indeed part of the pool, to which Merrill responded that the campaign was trying to follow the protocol established by the White House and cited the campaign’s right to decline pool coverage. According to Martosko, Merrill then said foreign press was not the issue, and that the campaign did not consider the Daily Mail to be foreign press. (The Daily Mail has a major US-based operation.)

In a statement, Merrill said the Clinton campaign wants “a happy press corps as much as the press corps does”.

“And we work very hard to achieve that in tandem with them,” Merrill said. “It’s a long campaign, and we are going to do our best to find equilibrium and best accommodate interest from as many news outlets as possible, given the space limitations of our events.”

Martosko proceeded to drive roughly 75 minutes to Clinton’s first stop in Rochester after informing the Clinton campaign that he planned to show up at each pooled event, regardless of whether or not her campaign staff chose to grant him access.

In a statement on behalf of the Daily Mail, spokesman Sean Walsh said the outlet is “seeking an explanation from the Clinton campaign as to why this occurred as Mr Martosko was scheduled to be the designated print pool reporter in New Hampshire this morning”.

There are currently 14 news outlets – including the Guardian – participating in the Clinton travel pool, which is fashioned after the the pool set-up at the White House. Any outlet that has asked to participate, and therefore made the commitment to travel, has been approved by the reporters who oversee the rotation.

Monday’s dust-up will only add more fuel to a larger row between Clinton’s campaign and the reporters tasked with covering the Democratic frontrunner for president. The Clinton press corps convened a meeting earlier this month to discuss their frustrations with access while covering the campaign and to hash out a strategy moving forward.