China has announced retaliatory tariffs on $US60 billion ($81b) worth of US goods ranging from liquefied natural gas (LNG) to some aircraft and warned of further measures, signalling it will not back down in a protracted trade war with Washington.

Key points: Tariffs are in retaliation to Trump administration's proposal for higher tariffs on Chinese goods

Tariffs are in retaliation to Trump administration's proposal for higher tariffs on Chinese goods White House says China should not underestimate Donald Trump

White House says China should not underestimate Donald Trump Liquefied natural gas, beef, condoms, coffee are among the targeted US products

China's finance ministry unveiled new sets of additional tariffs on 5,207 goods imported from the United States, ranging from 5 to 25 per cent.

China's Commerce Ministry said in a separate statement Beijing's new set of proposed import tariffs on US goods were rational and restrained.

The ministry said timing of the implementation of the new tariffs on US goods would depend on the actions of the US.

White House economic adviser Larry Kudlow warned China after it announced its retaliatory tariffs, saying Beijing should not underestimate US President Donald Trump's determination to act on trade.

"They better not underestimate the President," Mr Kudlow said in an interview on Fox Business Network.

"He [Trump] is going to stand tough … They better not assume anything … The president is not about to back down.

"And the best news, I think, is we are coming together with the European Union to make a deal with them, so we'll have a united front against China and, I think, most of our trade team would tell you, we're moving close on Mexico … So, this unifies NAFTA and US-Europe, Australia, Japan — China is increasingly isolated with a weak economy."

China not bending to Washington's pressure

Chinese commerce ministry said timing of the implementation of new tariffs will depend on US actions. ( Reuters: Damir Sagolj )

The two countries have not had formal talks on the trade dispute since early June.

Still, two senior diplomats did meet earlier on Friday, on the sidelines of a regional summit in Singapore.

China is willing to resolve differences with the United States on an equal footing, the Chinese Government's top diplomat said after meeting US Secretary of State Mike Pompeo, but added they did not address their trade war too specifically.

The Trump administration ramped up pressure for trade concessions from Beijing this week by proposing a higher 25 per cent tariff on $270 billion worth of Chinese imports.

China immediately vowed to retaliate, though at the same time urged the US to act rationally and return to talks to resolve the dispute.

The US and China implemented tariffs on $46 billion worth of each others' goods in July.

Washington is expected to soon implement more tariffs on $21 billion in additional Chinese goods, which China has already announced it will match immediately.

"The US side has repeatedly escalated the situation against the interests of both enterprises and consumers," the Chinese Commerce Ministry said in its statement.

"China has to take necessary countermeasures to defend its dignity and the interests of its people."

Among US products targeted were a wide range of agricultural and energy products such as beef and LNG.

LNG's inclusion marks a deployment by Beijing of one of its last major weapons from its energy and commodities arsenal in its fight with Washington.

The market is not large by value compared with the around $16 billion per year of US crude that arrives in the country, but those levels could shoot up as Beijing forges ahead with its plan to switch millions of households to the fuel away from coal as part of its battle against smog.

Other US goods targeted by China also included semiconductors, some helicopters, small-to-mid-sized aircraft, condoms, beef, steel products and coffee.

Reuters