FILE - This combination of file photos shows North Korean leader Kim Jong Un, left, and Chinese President Xi Jinping.
FILE - This combination of file photos shows North Korean leader Kim Jong Un, left, and Chinese President Xi Jinping.

North Korea's state news agency has issued a rare direct criticism of China, citing commentaries from Chinese state media and warning that China should not "test the limits" of North Korea's patience.

"China had better ponder over the grave consequences entailed by its reckless act of chopping down the pillar of the DPRK-China relations," said a commentary published Wednesday by KCNA.

The commentary said calls by China for North Korea to abandon its nuclear program cross a line and violate its rights.

China's Global Times made such remarks Thursday, saying North Korea is grappling with a form of "irrational logic" when it comes to its nuclear program.

The Global Times further said China will not allow its border region with North Korea to be contaminated by North Korean nuclear activities.

China on Wednesday called for restraint in the standoff over North Korea's nuclear and missile programs following North Korean complaints that the United States was pushing the region closer to war.

In this April 15, 2017 photo, a missile is paraded
FILE - In this April 15, 2017 photo, a submarine missile is paraded across Kim Il Sung Square during a military parade, in Pyongyang, North Korea to celebrate the 105th birth anniversary of Kim Il Sung, the country's late founder.

Chinese President Xi Jinping, in a phone call with Philippine counterpart Rodrigo Duterte, urged all parties in the standoff to use restraint and return to the negotiating table as soon as possible, Chinese state radio reported.

In his daily briefing, Chinese Foreign Ministry spokesman Geng Shuang said, "We again urge all relevant parties to remain calm and exercise restraint, stop irritating each other [and] work hard to create an atmosphere for contact and dialogue between all sides."

North Korea said Tuesday military exercises in the region by the U.S. and its allies amounts to "reckless military provocation" that is "pushing the situation on the Korean peninsula closer to the brink of nuclear war."

The United States recently sent an aircraft carrier to Korean waters.  In another show of strength, two U.S. bombers this week joined South Korean and Japanese military planes in regional training drills.

An F/A-18E Super Hornet from the Strike Fighter Sq
An F/A-18E Super Hornet from the Strike Fighter Squadron (VFA) 137 “Kestrels” takes off from the aircraft carrier USS Carl Vinson (CVN 70) flight deck in South China Sea, April 12, 2017.

North Korea said the bombers conducted "a nuclear bomb dropping drill" in its territory, while saying Trump and "other U.S. warmongers are crying out for making a preemptive nuclear strike" on the country.

"The urgent task is to lower temperatures and resume talks," Shuang said about the aerial military exercises.

The United States has urged China, North Korea's only major ally, to do more to reign in the reclusive country.  The administration of U.S. President Donald Trump has warned North Korea that the "era of strategic patience is over."

The participation of the two U.S. bombers in the exercises occurred as Trump unexpectedly said he would be "honored" to meet North Korean leader Kim Jong Un under the appropriate circumstances.

Tension on the Korean peninsula has been escalating for weeks, fueled by concern North Korea may conduct its sixth nuclear test in defiance of U.N. Security Council resolutions.