The world's largest asset manager BlackRock Inc. urged Exxon Mobil Corp. to "enhance its disclosures" regarding risks related to climate change.

Less than two weeks ago, shareholders approved a measure calling for increased transparency on climate change, a resolution supported by BlackRock and other large institutional funds.

BlackRock also said it requested to meet Exxon's independent directors over the past two years.

However, the world's largest publicly traded oil company declined to make directors available, citing a non-engagement policy between board members and shareholders.

BlackRock is Exxon's third largest investor with a more than 4 percent stake, according to Thomson Reuters data.

Exxon was not immediately available for a comment.