A US official has told AP news agency that the US military has suspended Paula Broadwell's security clearance.
President Obama praised the work of former CIA chief General David Petraeus. Speaking to reporters he said the General had served America "with great distinction" and from what he knows at "this point in the investigation", did not act in a way that compromised national security.
"I have no evidence, from this point, from what I have seen, that classified information was disclosed that would have impacted on our national security."
President Obama has said he had seen no evidence that former CIA chief General David Petraeus compromised national security during his affair:
The news conference will begin broadcasting live at 6:30pm UK time.
The Royal United Services Institute (RUSI) has postponed the presentation of its highest honour to General David Petraeus. A spokesman said:
David Petraeus will testify before the Senate Intelligence Committee regarding the attack on the US consulate in Benghazi. Dianne Feinstein, the Senate Intelligence Committee Chairman, told Politico:
"Mr Petraeus has indicated his willingness. He is eager to come before the committee so we will work out the details."
Mr Petraeus has not been seen since Friday, when the news of his affair with Mrs Broadwell broke.
The head of NATO, General Anders Fogh Rasmussen, said he had "full confidence" in General John Allen.
US Defence Secretary Leon Panetta warned against "leaping to any conclusions" about the country's top commander in Afghanistan, General John Allen.
President Obama has "faith" in General John Allen, the top US and NATO commander in Afghanistan, the White House spokesman Jay Carney said.
General Allen is under investigation for what the Pentagon described as "inappropriate communications" with the women whose complaint to the FBI led to the scandal involving General David Petraeus's affair.