(Updates prices, adds European futures)
* Pyongyang says it is considering missile strike on Guam
* Trump says any threat to US will be met with "fire and fury".
* U.S. Treasuries, yen, gold gain on risk aversion
* Nikkei skids more than 1 pct as yen strengthens
By Lisa Twaronite
TOKYO, Aug 9 (Reuters) - Asian shares and U.S. stock futures slipped on Wednesday and investors sought havens such as U.S. Treasuries, gold and the yen as tensions on the Korean peninsula escalated, with Pyongyang saying it is considering plans to attack Guam.
European bourses also looked set to open lower across the board, with Eurostoxx 50 futures already down 0.7 percent in early trade.
A spokesman for the Korean People's Army said in a statement that it was "carefully examining" plans for a missile attack on the U.S. Pacific territory, which has a large American military base.
The comments came just hours after U.S. President Donald Trump told North Korea that any threat to the United States would be met with "fire and fury", rattling markets globally.
MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.5 percent, while Japan's Nikkei lost 1.3 percent as the stronger yen sapped investor appetite.
South Korean shares, which have been among the strongest performers in the world so far this year, fell 1 percent, while the won lost around 0.6 percent to 1,134.70 to the dollar. Both hit more than one-month lows.
Financial markets have tended to quickly shake off North Korea's periodic sabre-rattling in the past, dismissing it as bluster, but tensions have lingered this year amid signs that it is making progress in its ballistic missile programme and on Trump's growing frustration with Pyongyang.
"The sell-off caused by geopolitical tensions on North Korea will likely be short-lived as long as both Trump and Kim Jong Un keep making feints against each other and neither takes military action," said Tomoaki Fujii, head of the investment research division at Akatsuki Securities Inc in Tokyo.
"The market's dent only lasted for a week in April when tension rose between them after North Korea launched a missile. Both countries know that there is no turning back once they push the button," Fujii said.
Others believe North Korea has no intention of backing down.
"Tensions will continue to mount and could eventually develop into a 'black swan' event that the markets are not prudently considering," Steve Hanke, professor of Applied Economics at the Johns Hopkins University, told the Reuters Global Markets Forum on Wednesday.
Though Hanke said he did not expect a sustained sell-off in riskier Asian assets, he added "safe assets, as a class, are probably underpriced at present."
S&P 500 e-mini futures were down 0.2 percent, hinting at weakness on Wall Street later in the day. The dollar notched a two-month trough on the safe-haven Japanese yen and was last down 0.3 percent at 109.99 .
The yen tends to benefit during times of geopolitical or financial stress as Japan is the world's biggest creditor nation and there is an assumption investors there will repatriate funds should a crisis eventuate.
The euro slid 0.6 percent to 128.92 yen, and fell 0.1 percent against the dollar to $1.1735.
"It's a clear case of 'risk-off' sentiment lifting the yen, as investors focus on the latest developments with North Korea," said Kumiko Ishikawa, FX market analyst at Sony Financial Holdings in Tokyo.
The dollar index, which tracks the greenback against a basket of six major rivals, was nearly flat on the day at 93.646, remaining above last week's 15-month low of 92.548.
The yield on the benchmark 10-year U.S. Treasury note fell to 2.255 percent from its U.S. close of 2.282 percent on Tuesday.
U.S. stocks closed lower on Tuesday after Trump's vow to respond aggressively to any North Korean threats triggered a late afternoon selling spree.
Spot gold added 0.4 percent to $1,265.18 an ounce, pulling away from the previous session's two-week lows.
Crude oil prices extended their slide as exports from key OPEC producers rose, despite news of lower crude shipments from Saudi Arabia.
U.S. crude shed 20 cents to $48.97 a barrel, while Brent crude fell 26 cents to $51.88 a barrel.
Additional reporting by Marika Tsuji and Ayai Tomisawa in Tokyo, and Divya Chowdhury in Mumbai; Editing by Eric Meijer and Kim Coghill