Bern, Switzerland - Postal traffic to the US plunged more than 80% following Washington's imposition of new tariffs, with 88 countries fully or partially suspending services, the Universal Postal Union said Saturday.

The UPU, the United Nations' postal cooperation agency, is working on "the rapid development of a new technical solution that will help get mail moving to the United States again," its director general Masahiko Metoki said in a statement.

President Donald Trump's administration announced in late July that it was abolishing a tax exemption on small packages entering the US from August 29.

The move sparked a flurry of announcements from postal services, including in Australia, Britain, France, Germany, India, Italy, and Japan, that most US-bound packages would no longer be accepted.

China Xi and Putin discuss immortality and organ transplants in bizarre hot mic moment

North Korea Kim Jong-un touts friendship with China after historic meeting with Xi Jinping

The UPU said data exchanged between postal operators via its electronic network showed that traffic to the US was down 81% on August 29, compared to a week earlier.

"Furthermore, 88 postal operators informed the UPU they have suspended some or all postal services to the US until a solution is implemented," it said.

These included Germany's Deutsche Post, Britain's Royal Mail, and two operators in Bosnia and Herzegovina.

Based in the Swiss capital Bern, the UPU was established in 1874 and counts 192 member states. It sets the rules for international mail exchanges and makes recommendations to improve services.