Indonesian officials said Tuesday they would ease import duties on goods including US steel and pledged to buy more American products in response to President Donald Trump's tariffs, before a delegation heads to Washington for talks.

It came as Indonesia's benchmark stock index plunged more than seven percent by the close of play Tuesday, its biggest fall since 2011.

Trump has taken aim at countries running a trade surplus with Washington and Indonesia has pledged to negotiate instead of retaliate to the 32 percent levy he imposed on Southeast Asia's biggest economy.

At an event in capital Jakarta held in response to the turmoil, Finance Minister Sri Mulyani Indrawati said that Indonesia would adjust import taxes on some commodities from 2.5 percent to 0.5 percent, including mobile phones and laptops.

"Anything that can reduce tariffs, because of the existing tariff burden from the US which has yet to go down, we will try to carry it out," she said.

Other products, including US steel and medical equipment, would be granted lower import duties of 0 percent to 5 percent, down from 5 percent to 10 percent, she said.

President Prabowo Subianto said he has told ministers to ease import quotas on some goods, without specifying.

"In my heart... actually it is possible that President Trump helped us," he told the meeting.

"He is forcing us to be lean, so we are efficient, so we are not spoiled."

Indonesia's chief economic minister Airlangga Hartarto is expected to lead a delegation to Washington later this month in hope of striking a better deal.

He said Tuesday that Indonesia would buy more US products to narrow its trade surplus with Washington, including wheat, liquefied natural gas and liquefied petroleum gas.

The United States is one of Indonesia's top trading partners, and Jakarta enjoyed a $16.8 billion trade surplus with Washington last year, according to Indonesian government data.