India lobbed a small but strategic strike in President Donald Trump's trade war, slapping retaliatory tariffs on 28 products and layering in another economic stressor just days before leaders from both nations meet at the G-20 summit.

The penalties run as high as 70%, affecting agricultural goods such as apples and almonds, as well as chemical and finished metal products. India said the move was "in the public interest" following Trump's decision to revoke India's preferential trade privileges.

India was the biggest beneficiary last year of the Generalized System of Preferences, a program designed to help developing countries sell to U.S. consumers. But Trump ended India's favorable trade treatment on June 5, irritated by the United States' hefty trade deficit — an estimated $21.3 billion, federal data show — with New Delhi. India imported a little more than $33 billion in U.S. goods in 2018, and sold $54.4 billion to the U.S.

Though India's action affects an estimated $241 million in imports — a pittance compared with the numbers involved in the White House's trade battles with China and Mexico — it's another pressure point in an increasingly tense and uncertain global economic outlook.

The tariffs took hold on Sunday, just ahead of next week's Group of 20 summit in Osaka, Japan, where economists and business leaders are anticipating a meeting between Trump and Chinese leader Xi Jinping about the trade war.

"This is a big deal," tweeted Michael Kugelman, deputy director of the Asia Program at the Wilson Center, a Washington-based think tank. "Not as much because of the value of the goods soon to be taxed ... but more so because now, Delhi's reaction to Washington's moves had been strikingly restrained."

The potential fallout from the U.S.-China conflict extends well beyond their respective borders, political leaders and economists said. In a G-20 briefing note, Christine Lagarde, managing director of the International Monetary Fund, warned that the last round of proposed tariffs against China could erase $455 billion to global GDP in 2020.

"There is strong evidence that the United States, China and the world economy are the losers from the current trade tensions," Lagarde wrote.

But in pre-summit meetings in Japan, U.S. Treasury Secretary Steven Mnuchin insisted the trade war wasn't dampening global growth or straining the domestic economy.

"I don't think in any way that the slowdowns you're seeing in parts of the world are a result of trade tensions at the moment," Mnuchin told reporters, the New York Times reported.

The Indian government had been mulling higher penalties on U.S. exports since last summer, after it was hit by Trump's tariffs on aluminum and steel, but reportedly held back, leaving room for de-escalation through trade talks.