(Reuters) - Vanguard said its funds supported the election of Exxon's director nominees at its annual meeting last week, but the mutual fund giant cited lingering concerns about the energy company's lawsuit against climate activists.

All 12 of the company's directors were re-elected at the company's annual meeting on May 29 including Exxon Chairman Darren Woods and Lead Director Joseph Hooley. The two were opposed by environmental activists after Exxon refused to end its lawsuit against proponents who had put forward a climate-measure at the meeting, even after they dropped it.

Pennsylvania-based Vanguard cited Exxon's decision in a recent note posted on its website.

"While the company's decision to continue to pursue the lawsuit gives us some pause given the potential chilling effect on future shareholder proposals, we do not, at this time, see evidence that the (Exxon) board has overseen actions that have negatively impacted shareholder returns," Vanguard wrote.

A Vanguard spokesman declined further comment.

An Exxon representative said the proponent of the since-withdrawn resolution "has not conceded that their proposal violated SEC rules. This is the question at the heart of our lawsuit: to seek clarity on the SEC proxy rules ... and thereby foster an environment for open and meaningful shareholder dialogue."