Taiwan said Thursday that it has sought US help in investigating an internet death threat against President Ma Ying-jeou's two daughters, who live in the United States, DPA reported.
The Bureau of Criminal Investigation made the request after a death threat against Ma's daughters was posted Wednesday.
"We see it as an act of terrorism and have sought help from US police in probing it," Ho Chao-fan, deputy chief of the bureau's international affairs division, told reporters.
The Chinese-language message was posted on a website run by Yahoo Inc but was deleted two hours later.
The message warned that Ma's daughters should not think they are safe because they live in the US and called on US-based Taiwanese to kill Ma's daughters.
The bureau traced the origin of the message to the US but needs US authorities' help to identify the person who posted it.
Ma's daughters - Leslie Ma, 30, and Kelly Ma, 24 - have been living in the US for several years.
Leslie Ma, who has both Taiwan and US citizenship, works with Chinese-American fireworks artist Cai Guoqiang and lives in New York while Kelly Ma is studying at Brown University in the eastern state of Rhode Island.
President Ma, who has improved relations with China since taking office in May 2008, has been criticized by the pro-independence, opposition Democratic Progressive Party (DPP) of supporting Taiwan-China unification, which Ma has denied.
The DPP condemned the threat against Ma's daughters. Chai Trong-rong, a DPP lawmaker, said if some Taiwanese oppose Ma, they should direct it to Ma, not his daughters.