LOS ANGELES- Dianne Feinstein, a senior United States senator from California, Thursday continued denouncing Trump administration's tariff policy to China, saying "the president's misguided actions are already causing real harm to our agricultural community."

The 84-year-old senator is the oldest currently serving United States senator and the longest current-serving female US senator.

"President Trump's trade war means that 90 percent of California's leading nut and fruit exports are hit with retaliatory tariffs. The president's misguided actions are already causing real harm to our agricultural community, and additional tariffs could bring even more damage." Feinstein tweeted Thursday morning.

She attached a graphic released by the California Department of Agriculture and Food on her official tweeter page, which shows total value of California agriculture exports to China in 2016 was $2 billion and China has become the third largest oversea market for California agriculture.

Two hours later, Feinstein posted another tweet, "China is a leading destination for California pistachios, almonds, wine and citrus products. The Trump administration must make it clear how they plan to protect American farmers from a costly trade fight with the world's second-largest economy."

It is not the first time that the Senate veteran queried Trump's trade policy in light of the dispute of the United States and China that ignited by Washington.

On April 4, Feinstein tweeted: "The president is putting obstacles in the way of American exports by inviting retaliatory tariffs from other countries. California farmers face enough challenges in the global market without Trump's unnecessary trade war."

"President Trump's trade war will hit California farmers hard. $2 billion worth of CA exports - including all exported almonds, walnuts, raisins, plums, grapes, kiwis, dates and figs - will now be subject to a 15 percent tariff when exported to China. How does that protect American jobs?" another tweet posted by her at the same day read.

She also wrote a public letter to Sonny Perdue, US Secretary of Agriculture, on April 4, calling on the administration to take steps to protect California's agriculture from Trump's escalating trade dispute with China.

"President Trump has stated that the recent tariff announcements are intended to protect American jobs, but so far the only concrete result appears to be fewer markets and higher costs for farmers and ranchers," Feinstein said. "International trade is increasingly important and I am concerned that the voices of our farmers are not being heard by the administration."

"Earlier this year, President Trump stated that in every decision his administration makes, he aims to honor America's strong farming legacy, but putting farmers in the crosshairs of an international trade dispute does just the opposite."

"Hardworking farmers in California and throughout the United States deserve better than to be a pawn in a global trade war." the letter concluded.