North Korea’s recent announcement that it has restarted the Yongbyon nuclear complex and an earlier statement about its readiness to launch long-range rockets have been met with a warning of increasingly “severe consequences” for the communist state by U.S. Secretary of State John Kerry.

Speaking to reporters on Thursday, Kerry said that it may take more than sanctions to get North Korea to give up its nuclear weapons program, as the country is already isolated from the global economy.

Kerry did not elaborate on what those additional sanctions may be, other than noting that China was distancing itself from North Korea and that he and Russian Foreign Minister Sergey Lavrov had discussed the North Korean situation with the goal of restarting diplomacy.

Since reaching a landmark deal in September 2005 to give up its nuclear program in return for economic aid, North Korea has conducted three nuclear tests – in 2006, 2009, and 2013 – all following U.N. sanctions that were imposed after North Korean launches. Meanwhile, the six party talks aimed at denuclearization of North Korea have been stalled since April 2009.

If there is to be any use of a long-range missile, ostensibly to launch a satellite, it is likely to occur around Oct. 10, the 70th anniversary of the founding of the Workers’ Party. In the event of such a launch, the U.N. is certain to impose further sanctions against North Korea. If Kim Jong-un chooses to follow the past pattern, he would then retaliate with a nuclear test.

China reacted unusually swiftly to North Korea’s threats, a palpable sign of growing distance between the two traditional allies. On Tuesday, a representative of China’s Foreign Ministry said that Beijing was committed to peace and stability on the Korean Peninsula and called for dialogue.

It appears that Kim is back to the usual North Korean exercise of brinkmanship: Create a crisis situation and force your enemies, in this case the U.S., to come to the negotiating table, at which North Korea will attempt to extract aid and concessions.

However, this antic has been tried one too many times. The U.S. may very well choose to impose further sanctions and penalties against Pyongyang if it carries out its threats.

North Korea’s latest threats have dampened the recent conciliatory mood that followed the Aug. 25 agreement between Seoul and Pyongyang. The possibility that the North may unilaterally cancel the upcoming reunion of separated families in retaliation notwithstanding, Seoul should unequivocally warn Pyongyang that any missile launch or nuclear test will be met with consequences.