Yesterday Politico reported that President Trump would block the release of the JFK files. Today, President Trump tweets:

WASHINGTON (Reuters) – U.S. President Donald Trump said on Saturday that, subject to receipt of further information, he planned to allow the opening of long-secret files on the November 1963 assassination of President John F. Kennedy due for release next week.
[…]  Over the years, the National Archives has released most documents related to the case, but a final batch, amounting to tens of thousands of pages, remains and only Trump has the authority to decide whether some should continue to be withheld or released in redacted form.

The Washington Post and other media have quoted officials as saying that government agencies have lobbied Trump to withhold some of the documents, arguing that they could expose relatively recent intelligence and law enforcement operations. (read more)