The United States is reportedly weighing tough sanctions against North Korea to bar its access to the global financial system.

US government officials said the sanctions are meant to build up economic and diplomatic pressure on Pyongyang over its nuclear and missile tests, Reuters reported.

The officials, speaking on condition of anonymity, added that the punitive measures are part of proposals being drawn up by the US National Security Advisor H.R. McMaster and could be finalized within weeks.

The sanctions would particularly target Chinese banks and firms that do the business with North Korea, according to the administration officials familiar with the deliberations.

Last week, US Secretary of State Rex Tillerson warned Pyongyang of military action, saying Washington’s policy of strategic patience on the North is over.

In response, the North Korean government said it’s prepared for “any war” the US wants.

"The nuclear force of (North Korea) is the treasured sword of justice and the most reliable war deterrence to defend the socialist motherland and the life of its people," the official Korean Central News Agency quoted the spokesman as saying.

The unidentified spokesman said the US should accept that North Korea is a nuclear-capable nation that "has the will and capability to fully respond to any war the US would like to ignite."

"If the businessmen-turned US authorities thought that they would frighten (North Korea), they would soon know that their method would not work," the official was quoted as saying.

State media on Sunday reported that North Korea had conducted a test of a new high-thrust engine at its rocket launch station and leader Kim Jong-un said the successful test marked "a new birth" of the country’s rocket industry.

North Korea has so far conducted five nuclear tests and numerous missile launches.