The United States has temporarily deployed an additional Patriot missile battery in South Korea in response to North Korea’s nuclear test and a long-range rocket launch.

The move comes ahead of talks next week to set up an even more sophisticated US missile defence system in a move that has worried China and Russia.

The new tough stance follows South Korea’s decision to shut down an inter-Korean factory park that had been the rival Koreas’ last major symbol of cooperation, but that Seoul said had been used by North Korea to fund its nuclear and missile programs. North Korea responded by deporting South Korean citizens, seizing South Korean assets and vowing to militarize the park.

South Korea on Friday cut off power and water supplies to the industrial park and announced that its planned talks with the United States on deploying the Terminal High-Altitude Area Defense, or THAAD, one of the most advanced missile defense systems in the world, could start next week. Officials say they have yet to set a specific starting date for the talks.

In the meantime, the US military command in South Korea said Saturday that an air defense battery unit from Fort Bliss, Texas, has been conducting ballistic missile training using the Patriot system at Osan Air Base near Seoul.

Lt. Gen. Thomas Vandal, commander of the US Eighth Army, said “exercises like this ensure we are always ready to defend against an attack from North Korea.”

“North Korea’s continued development of ballistic missiles against the expressed will of the international community requires the alliance to maintain effective and ready ballistic missile defenses,” he said in a statement.

A spokeswoman for US Forces Korea couldn’t confirm how long the Patriot missile battery from Texas would be deployed in South Korea. The US military already has an operating Patriot missile defence system in South Korea to counter the threat of North Korea’s shorter-range arsenal and medium-range missiles.

US secretary of state John Kerry, right, and South Korea’s foreign minister Yun Byung-se shake hands during a meeting in Munich. Photograph: Matthias Schrader/AP

South Korean media have long speculated that the two countries are working on a THAAD deployment in South Korea, but it took the North’s rocket launch last Sunday, which outsiders see as a test of banned ballistic missile technology, for the allies to formally announce they will begin the missile defense talks.

Beijing and Moscow are sensitive to the possibility of THAAD in South Korea; critics say the system could help US radar spot missiles in other countries.

China’s state media quickly made the country’s displeasure known, while Russia also expressed worries about the deployment. North Korea has previously warned of a nuclear war in the region and threatened to bolster its armed forces if the THAAD deployment occurs.

In Munich, US secretary of state John Kerry met with his Chinese and South Korean counterparts to discuss the response to North Korea’s actions, including the missile system. In talks with South Korean foreign minister Yun Byung-se, Kerry expressed support for Seoul’s decision to shut down the factory park in the North Korean border town of Kaesong and discussed a broad range of potential sanctions against the North, South Korea’s foreign ministry said.

Seoul and Washington want to deploy the system at an early date and the upcoming talks will discuss where and exactly when the deployment can be made, a South Korean defense official said, requesting anonymity because of department rules.

The official said the THAAD deployment is designed to protect South Korea from North Korean threats and isn’t targeting China or anyone else.

The current standoff flared after North Korea carried out a nuclear test last month, its fourth, followed by the long-range rocket launch on Sunday. Pyongyang said the launch, which put an Earth observation satellite into orbit, is part of a peaceful space program.