As President Donald Trump and his chief of staff on Sunday escalated their tariff threats on Mexico's government, alarm bells were sounding around the globe on fears of increasing protectionism.

"People have been saying for years that we should talk to Mexico. The problem is that Mexico is an 'abuser' of the United States, taking but never giving. It has been this way for decades," wrote Trump over Twitter, before his White House Chief Mick Mulvaney made his usual rounds on Sunday talk shows on Fox News and NBC's "Meet the Press."

"The president is deadly serious about fixing the situation at the southern border, this is not the first time I'm on your program talking about what's happening on the Mexican U.S. border," Mulvaney told Fox News Sunday host Chris Wallace, according to a transcript provided by Fox.

Late on Thursday Trump said he'd impose tariffs on Mexican imports to the U.S. -- from 5% to potentially 25% by October -- if the southern neighbor didn't stop illegal and undocumented immigration across its border to the north. The announcement -- amid the hot trade war with China -- hit automotive company stocks especially hard.

But following the tariff warning, fears of rising protectionism gave industry groups around the globe heightened anxiety. The International Air Transport Association even downgraded its 2019 outlook for air transport industry profit by $7.5 billion to $28 billion from the $35.5 billion that was forecast in December in part on worries of trade fights and protectionism.

"Aviation needs borders that are open to people and to trade. Nobody wins from trade wars, protectionist policies or isolationist agendas. But everybody benefits from growing connectivity. A more inclusive globalization must be the way forward," said t he group's director general and chief executive, Alexandre de Juniac, in press statements.

Automakers in Japan were also bracing for any increase in tariffs, and the president's tweets prompted Japanese Economy Minister Toshimitsu Motegi to last week warn the fees would have unpleasant global economic consequences, according to a report in the Japan Times.

Watching the tensions rise between Beijing and Washington, Morgan Stanley chief economist Chetan Ahya also forecast Sunday that a recession could start within a year if the U.S. indeed increases tariffs to 25% on $300 billion worth of additional Chinese imports -- and China responds in kind -- according to a report in Bloomberg.