U.S. Secretary of State Mike Pompeo on Tuesday invoked the 30th anniversary of the demise of communism to implore countries in Central and Eastern Europe to resist Chinese and Russian influence, AP reported.

Speaking in the Slovak capital of Bratislava, Pompeo said China and Russia pose twin threats to the democratic and free-market gains made since the fall of the Berlin Wall in 1989.

He said the post-communist countries are particularly vulnerable to Chinese and Russian predatory investment and political meddling. To combat the threat, he said, the United States is committed to boosting its engagement in the region, through defense cooperation agreements and exchange programs.

He said because of its history and geography, Slovakia has “a special appreciation for the aggressive role Russia continues to play in the region,” particularly in Ukraine.

Pompeo said he had raised with Slovak officials the “need to guard against China’s economic and other efforts to create dependence and manipulate your political system.”