WASHINGTON, Feb. 12 (Yonhap) -- U.S. Republican presidential candidate Ted Cruz has sent a letter to President Barack Obama, urging him to impose full-scale sanctions on North Korea and declare China is no longer a U.S. partner in efforts to end Pyongyang's nuclear program.

In a four-page letter, Cruz also called for beefing up U.S. naval forces, deploying the Terminal High Altitude Area Defense (THAAD) missile defense system to South Korea and relist the North as a state sponsor of terrorism.

"Your administration has, for too long, hoped to achieve denuclearization through failed diplomacy and limited sanctions," Cruz said in the letter dated Wednesday. "The nuclear tests of May 2009, February 2013 and January 2016 suggest that 'strategic patience' with a country still officially at war with us is not working."

The Texas senator said the U.S. should use its actions against Iran as a model for imposing the same severity of targeted financial measures against the North and should no longer hold some sanctions in abeyance, to be rolled out after the next North Korean violation or provocation.

"There will be little change until North Korea feels the full impact of sanctions and China feels concern over the consequences of Pyongyang's actions and its own obstructionism. The U.S. needs to sharpen the choices for North Korea by raising the risk and cost for those who choose to violate laws and resolutions," he said.

Cruz also argued that lax enforcement of U.S. laws have made China complacent in policing the illicit financing of regimes like the North and Iran, thus becoming complicit in their proliferation. He also claimed that China allows North Korean arms shipments to Iran to travel unimpeded through Chinese ports and airspace.

He also accused China of transferring transporter-erector-launchers to North Korea in 2011, which Pyongyang modified with the ability to launch the KN-08, a road-mobile intercontinental ballistic missile capable of reaching the west coast of the U.S.

"It is time to tell the truth about China: the PRC is not our partner in denuclearizing the Korean peninsula," he said.

Cruz claimed THAAD is more capable than any ballistic missile system that South Korea has or will have for decades and the THAAD deployment is wholly in line with China's stated goal of preserving stability on the Korean peninsula and would not in any way constrain China's military capabilities.

"If the U.S. is serious about defending South Korea, we must openly confront China's support for North Korea," he said. "The U.S. should strongly push back against China's opposition to THAAD by rebutting its false assertions that the system would impact Chinese security."

Cruz said there is ample justification for putting Pyongyang back on to the list of states sponsoring terrorism, including its cyber attacks and accompanying threats of a "9/11-type attack." The North is also suspected of providing weapons to militant groups like Hezbollah and Hamas, he said.

"Until such actions are taken, the North Korean threat will continue to metastasize. Their launch last Saturday (U.S. time) is further evidence of the escalating danger the DPRK poses to the U.S. and our allies," he said.

Source: Yonhap news