Hillary Clinton's chief of staff Cheryl Mills's received nearly 150 phone messages from Clinton Foundation's operations director Laura Graham during a two year span at the State Department, according to phone logs - a significantly higher number of calls than from any other individual during that time frame.

The phone logs, which were obtained by Fox News and cited by reporter James Rosen during the State Department press briefing on Monday, raise fresh questions about the close contact between the Clinton Foundation and Clinton's State Department office during her tenure.

State Department spokesman Mark Toner confirmed during the briefing that he had seen the phone logs, which showed Mills had received nearly 150 calls from Clinton Foundation COO Laura Graham.

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Hillary Clinton's chief of staff Cheryl Mills's received nearly 150 phone messages from Clinton Foundation over two years (pictured, Hillary Clinton this week)

Mills was working as Clinton's chief of staff at the State Department at the time. Clinton had signed an ethics agreement with the Obama administration before taking office that was intended to create a firewall between her office and her family's foundation, which received millions in donations from foreign and corporate donors.

The incoming phone messages to Mills were logged into spreadsheets by Mills's assistant. Rosen said Fox News obtained 180 pages of these logs through a public records request, and found that Graham 'left the greatest number of messages for Mills by an exponential order.'

Toner said the documents did not show any evidence of inappropriate contact between the foundation and Clinton's State Department, adding that the messages from Graham to Mills would not have violated Clinton's ethics agreement. He also said he did not know how many of the calls Mills returned.

'Secretary Clinton's ethics agreement at the time did not preclude other State Department officials from engaging with, or having contact with, the Clinton Foundation,' said Toner.

Mills (left) was working as Clinton's chief of staff at the State Department at the time

The number of calls Mills (pictured) received raise fresh questions about the close contact between the Clinton Foundation and Clinton's State Department

He also said it was 'no surprise' that there was a high level of contact between Mills and the Clinton Foundation, due to the fact that both were involved in the 2011 Haiti earthquake relief efforts.

'State Department officials were in contact with a range of outside individuals and organizations, including non-profits, NGOs, and of course think tanks and others,' said Toner.

State Department officials were in contact with a range of outside individuals and organizations, including non-profits, NGOs, and of course think tanks and others State Department spokesman Mark Toner

'I can't give you a readout of every one of those messages or every one of those calls rather and in fact how many of those calls were returned or connected,' he added.

'I would note that the State Department at the time, and certainly Cheryl Mills, individually, was a coordinating hub for U.S. and international relief efforts in the wake of the 2011 Haiti earthquake.'

Toner noted that Bill Clinton 'also played a role as a coordinator for relief efforts' while serving as the United Nations special envoy for Haiti, which may have been the explanation for the large volume of calls from the Clinton Foundation.

'I don't want to speculate, but that could well be the reason why there were these calls,' said Toner. 'Simply coordinating on what was one of the premier, or most significant, foreign relations issues of the time.'

The incoming phone messages to Mills were logged into spreadsheets by Mills's assistant (pictured, Clinton on Sunday)

When pressed on whether the calls indicated an inappropriately close relationship between the State Department and the Clinton Foundation, Toner said he has 'seen no evidence of any behaviour, any relations with the Clinton Foundation that weren't completely above board.'

In one phone message to Mills, Graham used the term 'our boss' – a possible reference to both women working for the same person – according to Rosen.

'Did Ms. Graham and Ms. Mills have the same boss?' Rosen asked during the press briefing.

'They did not have the same boss,' said Toner.

Mills held several outside positions while at the State Department, including a brief stint working for New York University's Abu Dhabi campus. She also stayed on the board of the Clinton Foundation for a brief period after joining State.

After Clinton stepped down in 2013, Mills stayed at the department under a special employment agreement that allowed her to take outside consulting jobs.

Clinton's presidential rival Donald Trump (pictured) is calling for the Clinton Foundation to be 'shut down immediately'

Toner also responded to questions on a New York Post report on Clinton aide Huma Abedin's prior job editing a Muslim journal that published harsh critiques of women's rights and tied the Sept. 11 attacks to U.S. foreign policy. The Journal of Muslim Minority Affairs, which is run by Abedin's mother, listed Abedin as an assistant editor for a decade.

Toner said he did not know whether State Department officials were aware of Abedin's work for the publication, or whether this information came up while Abedin was being vetted for a security clearance at the State Department.