A growing number of developers and other industry professionals, some of which are Sony employees, have told CVG that Microsoft will reveal its next generation Xbox for the first time in April.
One senior Sony official, who asked not to be named, said he was informed that the PS4 showcase in New York had "at first caught Microsoft off-guard".
"We definitely ruffled some feathers," the person said.
It is said that Microsoft will now showcase its console at a one-off media event in April - though it is expected that discussion about future tech would be an inevitability if Microsoft engineers and developers attend GDC in March.
[UPDATE: Microsoft partner Ustechs, which has worked with the platform holder on previous media briefings such as the E3 2012 press conference, has registered the domain XboxEvent.com (as explained on NeoGAF)]
Microsoft has declined to comment on its next-gen plans ever since rumours began two years ago.
Sony revealed the PlayStation 4 at a New York press conference on Wednesday.
The PS4 release date is set for "holiday 2013", likely across Japan, Europe and the US.