BP's board of directors unanimously removed Chairman Albert Manifold on Tuesday, citing "serious concerns" related to governance standards, oversight and conduct. The removal was effective immediately, less than a year after Manifold was appointed to the position.

The London-based oil giant announced that Ian Tyler would serve as interim chairman while the company begins searching for a permanent replacement. BP declined to provide specific details about the nature of the conduct issues that led to Manifold's dismissal.

The BBC reported that "bullying" and "overbearing" behavior were behind the abrupt removal, though BP declined to comment on whether such behavior was part of the reason for the dismissal. The departure was described as unexpected given Manifold's recent appointment.

BP shares fell 6% in pre-market trading following the announcement. The company is one of the world's five largest oil production and exploration companies by revenue and operates in approximately 60 countries.

The leadership change comes as BP continues to navigate challenges including its recovery from the 2010 Deepwater Horizon disaster, which killed 17 workers and resulted in billions of dollars in environmental damage payments. Industry analysts have previously suggested that BP's abandoned shift toward renewable energy has left its shares undervalued compared to other major oil companies.