SEOUL (Reuters) - General Motors has agreed to provide $3.6 billion in fresh funding to its troubled South Korean unit, higher than its previously proposed $2.3 billion as part of a preliminary deal, South Korea said on Thursday.

State-funded Korea Development Bank also said the U.S. automaker agreed to swap all of the debt owed by its South Korean unit to the headquarters into equity.

The KDB, which owns a 17 percent stake in GM Korea, also plans to invest a total of $750 billion in the unit.

(Reporting by Hyunjoo Jin and Ju-min Park; editing by Jason Neely)