In a dramatic shift from traditional policy, an internal White House review on North Korea strategy revealed that the option to use military force or a regime change to curb the threat of North Korean nuclear weapons was on the table, The Wall Street Journal reported on Wednesday.

This review comes at the heels of a report claiming President Donald Trump believed the “greatest immediate threat” to the US was North Korea’s nuclear program.

Recent provocations from the Hermit Kingdom, including the ballistic missile launch in the Sea of Japan and the killing of Kim Jong Un’s estranged half-brother in Malaysia, may have provoked this shift in the policy that have many officials and US allies worried.

“North Korea just stated that it is in the final stages of developing a nuclear weapon capable of reaching parts of the U.S. It won’t happen!” Trump tweeted in January. Several weeks later, North Korea conducted its missile test.

Since then, Deputy National Security Adviser K.T. McFarland consulted with other officials to address North Korea’s fresh series of provocations. In the meeting, held about two weeks ago, the officials discussed the possibility of a plan “outside the mainstream,” The Journal reported.

According to The Journal, McFarland requested for all options to overhaul American policy toward North Korea — including for the US to recognize North Korea as a nuclear state and the possibility of a direct military conflict.

The proposals, which are being vetted before Trump’s review, would certainly be met with worry from China, a longtime ally of North Korea that recently responded with an export banagainst North Korea’s coal industry. Additionally, many experts fear that a direct military conflict would spark all-out warfare, including artillery barrages directed at Seoul, South Korea’s capital.

Even more worrisome is the possibility for further North Korean provocations, which may influence the recent policy shift, as early as this month. As the US and its ally South Korea conduct “Foal Eagle” and “Key Resolve,” their annual military exercises that involve 17,000 US troops and Terminal High Altitude Air Defense systems, experts say provocations from North Korea will be likely.