More than eight in 10 Americans say relations with South Korea are important while American support for the use of U.S. armed forces to defend the Asian ally stands at an all-time high, an opinion poll showed Tuesday.

The Chicago Council on Global Affairs released the survey results ahead of South Korean President Park Geun-hye's visit to Washington this week. Park is scheduled to hold talks with President Barack Obama at the White House on Friday.

"As President Park Geun-hye visits the United States, American opinion of South Korea is largely positive. Majorities say US-ROK relations are important and see South Korea as a reliable partner," the council said in a statement.

"Perhaps the most significant signal of American backing for the bilateral relationship is that U.S. public support for the use of U.S. forces to defend South Korea in the event of a North Korean attack is at an all-time high," it said.

According to the survey conducted on 2,034 adults aged 18 or older between May 25-June 17, 83 percent said relations with South Korea are important and 62 percent were in support of South Korea exerting strong leadership in world affairs.

The survey also showed 66 percent of Americans view South Korea as a reliable partner.

Public support for the use of U.S. forces to defend South Korea in the event of a North Korean attack reached 47 percent, an all-time high compared with less then 20 percent when the question was first asked in 1974, according to the survey.

Still, 49 percent opposed the idea of using U.S. forces to defend the South.

It also showed that 55 percent of Americans view the North Korean nuclear weapons program as a critical threat to the United States, while 75 percent favor continued diplomatic efforts to pressure North Korea to denuclearize, and 70 percent support increased economic sanctions.

Only 36 percent of the respondents were in support of U.S. airstrikes against the North's nuclear facilities, and even fewer Americans (25 percent) supported the use of ground troops to end Pyongyang's nuclear program, the survey showed.

In the event of inter-Korean unification, 32 percent of Americans favor maintaining the alliance with a unified Korea and keeping a U.S. troop presence in the country, while 44 percent said they favor maintaining the alliance after unification, but favor removing U.S. troops from the country, the survey showed. (Yonhap)