China’s Xi Jinping warned President Donald Trump to use “extreme caution” regarding arms sales to Taiwan, in a phone call between the two leaders.  

Taiwan was one of more than half a dozen topics Trump and Xi discussed during a “long and thorough” call Wednesday, Trump wrote on Truth Social.  

The two leaders discussed the war between Russia and Ukraine, Iran, and China’s purchases of U.S. exports, but Taiwan was central to the conversation, the New York Times reports.  

Beijing claims it must safeguard its territory, and considers Taiwan part of that territory, according to reporting from the South China Morning Post. 

In December, the Trump administration announced an $11.1 billion weapons sale to Taiwan, the largest arms agreement between the U.S. and Taiwan to date. 

The deal was announced as China continues to claim sovereignty over the island, but Taiwan operates as a democracy separate from the Chinese Communist Party.  

During Wednesday’s call, Xi reportedly told Trump that Taiwan is the “the most important issue in China-U.S. relations,” adding that China “will never allow Taiwan to be separated from China,” according to the Times. 

Following the call, Taiwan’s Foreign Ministry said it welcomes “efforts to ensure regional stability and shore up the status quo amid increasing [People’s Republic of China] pressure.”  

With the U.S. and “like-minded partners, we remain dedicated to a free, open and prosperous Indo-Pacific,” Taiwan’s Foreign Ministry wrote on X.  

Trump and Xi last spoke in November, following an in-person meeting in October in South Korea. At that meeting, they reached their current trade agreement, including China resuming purchases of U.S. soybeans.  

The two leaders are scheduled to meet again in April when Trump visits China.  

“The relationship with China, and my personal relationship with President Xi, is an extremely good one, and we both realize how important it is to keep it that way,” Trump wrote on Truth Social.

“I believe that there will be many positive results achieved over the next three years of my Presidency having to do with President Xi, and the People’s Republic of China!”