UPDATE 1-U.S. reassessing aid to Solomon Islands after Taiwan ties cut

(Adds details on past assistance from U.S. fact sheet)

WASHINGTON, Sept 18 (Reuters) - The United States is reassessing its assistance to Solomon Islands after the South Pacific nation cut ties with Taiwan in favor of China this week, a senior official in the U.S. Agency for International Development (USAID) said on Wednesday.

Solomon Islands was the sixth country to switch allegiance to China since President Tsai Ing-wen took office in Taiwan in 2016.

The move leaves Taipei with formal relations with only 16 countries, many of them small, less-developed nations in Central America and the Pacific.

Asked at a budget hearing in the House of Representatives Committee on Foreign Affairs whether any funds would be directed to Solomon Islands in fiscal 2020, Gloria Steele, acting assistant administrator of USAID's Asia bureau, replied: "We are reassessing our assistance to the Solomon Islands at this point."

Steele did not elaborate, and USAID did not immediately respond to a request for details.

On Tuesday, another senior U.S. official said Vice President Mike Pence had declined a request from the leader of Solomon Islands to meet to discuss development partnerships after it cut ties with Taiwan.

Solomons Prime Minister Manasseh Sogavare had asked Pence in July for a meeting, which was to have taken place on the sidelines of the United Nations General Assembly meeting in New York next week, or afterward in Washington.

"But the decision by the Solomon Islands to change its diplomatic recognition from Taiwan to the People's Republic of China has consequences. They're hurting a historically strong relationship by doing this," said the senior U.S. official who spoke on Tuesday.

The United States upholds what is known as the "one-China" policy, officially recognizing Beijing and not Taipei, while assisting Taiwan.

But while working to counter China's expanding global influence, Washington has criticized countries for switching diplomatic recognition from Taipei to Beijing.

According to State Department fact sheet from last year, USAID supports programs in Solomon Islands for disaster risk reduction and to counter the impact of climate change via assistance covering 12 Pacific Island countries.

The U.S. Coast Guard and military also trains security officials in Solomon Islands and the State Department said the United States provided $50,000 to assist with a dengue fever outbreak there in 2013 and $250,000 to help with Cyclone Ita flood recovery in 2014.

Beijing said on Tuesday Solomon Islands would have unprecedented development opportunities after cutting ties with Taiwan.

Solomon Islands' decision followed a months-long review of the pros and cons of a switch to Beijing, which was offering $8.5 million in development funds to replace support from Taiwan. (Reporting by David Brunnstrom Editing by Leslie Adler and Lincoln Feast.)