(Reuters) - Donald Trump's sweeping new tariffs on U.S. imports have targeted countries across the world in the most serious blow to the global trading system in decades.

They have prompted both retaliatory measures and efforts to negotiate a de-escalation. Here is how the United States' top 15 trading partners have reacted so far:

EUROPEAN UNION - The 27-country bloc is rolling out its first set of countermeasures in April against the U.S. tariffs on steel and aluminium. It watered down initial proposals, removing for example U.S. bourbon from that list, and has also offered a "zero-for-zero" tariff deal to Washington.

CHINA - Beijing struck back with matching 34% blanket tariffs on U.S. imports, export curbs on some rare earths, and by adding another 11 U.S. bodies to a list of "unreliable entities", which allows Beijing to sanction them. It vows to "fight to the end" on tariffs.

MEXICO - Mexico was left off Trump's global tariffs list but still has plenty of headwinds to navigate: U.S. levies up to 25% are still imposed on automobiles, steel, and aluminium, as well as on goods that do not comply with the USMCA trade pact among the North American countries.

CANADA - Canada imposed 25% tariffs on C$30 billion ($21 billion) in goods imported annually from the U.S. on March 6 in response to Trump's initial duties, plus 25% tariffs on a further C$29.8 billion worth of products imported from the U.S. in response to U.S. steel and aluminium tariffs. New auto tariffs announced on April 3 apply to car imports worth C$35.6 billion.

GERMANY - Berlin argues the EU's market of 450 million consumers gives it leverage to negotiate with Trump and avert a trade war. Government officials have also called on the EU to nurture trade deals with other countries such as Mexico, Canada and India.

JAPAN - Tokyo plans no slap counter-measures and instead will send a team to negotiate concessions from the United States. Prime Minister Shigeru Ishiba appointed his economy minister, Ryosei Akazawa, as negotiator, who will work with U.S. Treasury Secretary Scott Bessent in bilateral trade talks. Ishiba said he was considering a new U.S. visit to meet Trump.

SOUTH KOREA - There has been no retaliation from Seoul thus far but acting President Han Duck-soo ordered emergency support measures for affected businesses, including automobiles, and dispatched a senior official to Washington to try to negotiate.

TAIWAN - Taiwan President Lai Ching-te has proposed a zero tariff regime with the United States and said Taiwan will not levy reciprocal tariffs. Instead it will seek to boost imports from the United States and remove non-tariff barriers. 

VIETNAM - Vietnam's top leader To Lam offered to remove duties on U.S. goods in a call with Trump the day after the tariff announcement. It has made a slew of concessions, including pledging to import more U.S. goods and granting a licence to Elon Musk's Starlink under favourable conditions. The Trump Organization is also investing in golf facilities in Vietnam.

BRITAIN - Prime Minister Keir Starmer's government is in talks with the U.S. over a deal that could reduce its 10% tariffs. It is consulting with businesses on the need for retaliatory tariffs and measures to prevent dumping by other countries. It has said it wants to deepen trade ties with key partners.

INDIA - India has not planned retaliatory measures against the U.S. and aims to negotiate a bilateral trade deal with the U.S. It has also signalled its willingness to bring down tariffs on more than half of U.S. imports into the country. Alongside, it is also talking to Britain and the EU on trade tie-ups.

NETHERLANDS - The Netherlands, one of the world's largest agricultural exporters and home to Europe's largest sea port, has stressed the need for a calm and proportionate response to the U.S. tariffs, warning against escalation.

IRELAND - With a local economy highly dependent on a cluster of major U.S. pharmaceutical and technology firms, Dublin has called for a "calm, measured" response and has warned Brussels against the use of its powerful Anti-Coercion Instrument law.

ITALY - Rome has warned against retaliatory tariffs. To offset the economic hit from the U.S. moves, it has urged the EU to allow member states to raise spending without breaching the bloc's fiscal rules.

FRANCE - President Emmanuel Macron has called for a firm response from the European Union, possibly including U.S. digital services. He also urged French companies to put their U.S. investment plans on hold until the situation is clarified.

BRAZIL - Brazil's Congress reacted to Trump's tariffs by passing a law enabling trade retaliation. President Luiz Inacio Lula da Silva said any countermeasures would be based on that law. Vice President Geraldo Alckmin said the country prefers dialogue and will not trigger provisions in the new law for now.