* South Korean won skids as tensions with Pyongyang rise
* Passover, Good Friday observances thin liquidity
* Trump comments continue to pressure dollar, U.S. yields
TOKYO, April 14 (Reuters) - The dollar nursed losses on Friday, on track for a losing week as geopolitical tensions underpinned the perceived safe-haven Japanese currency.
The dollar index, which tracks the U.S. unit against a basket of six rival currencies, steadied at 100.560, flat on the day but down 0.6 percent for the week.
U.S. President Donald Trump said on Thursday that North Korea is a problem that "will be taken care of," as China urged caution and speculation rose that Pyongyang might be on the verge of a sixth nuclear test.
The dollar rose 0.6 percent against the South Korean won , which stood at 1,136.5.
In another part of the world, the U.S. military said on Thursday that it dropped "the mother of all bombs," the largest non-nuclear device it has ever unleashed in combat, on a network of caves and tunnels used by Islamic State in eastern Afghanistan.
"I think that the 'mother of all bombs' was intended to show the power of U.S. forces to North Korea," said Kaneo Ogino, director at foreign exchange research firm Global-info Co in Tokyo.
"But maybe we won't see big market moves today, because I think the short-term players already have put on short-dollar positions, and now everyone is just waiting for the next trigger," he said.
The dollar edged up 0.1 percent on the day to 109.17 yen , but was down 1.7 percent for the week.
Market liquidity was thinner than usual because of this week's Passover and Good Friday holiday observances around the world. The market for U.S. Treasuries finished trading early on Thursday, and will be closed Friday.
The benchmark U.S. Treasury yield skidded to its lowest levels since November on Thursday, after President Donald Trump said in a Wall Street Journal interview published late Wednesday that he favoured low interest rates.
He also said the dollar was "getting too strong" and would eventually hurt the U.S. economy.
"Yields declined, and were seeing a softening of the dollar," said Bill Northey, chief investment officer at the private client group of U.S. Bank in Helena, Montana.
"It's unique to see that level of focus coming from the White House on economic topics that haven't usually been the purview of the administration," he said, explaining why markets continued to focus on Trump's remarks.
The euro edged up 0.1 percent to $1.0617. It was up 0.2 percent for the week, though concerns about the outcome of France's presidential election continued to limit its upside.
Far-right National Front presidential candidate Marine Le Pen, who is campaigning on a platform of economic nationalism, says France's GDP growth would accelerate to 2.5 percent towards the end of her first term if she wins the upcoming election.
Polls have suggested Le Pen and centrist Emmanuel Macron will emerge the winners of the April 23 first round against leftist Jean-Luc Melenchon and conservative Francois Fillon, with Macron seen winning the May 7 run-off.
Against the yen, the euro slumped as low as 115.72 on Thursday, its lowest level since November, and was poised to drop 2.4 percent for the week. It last stood at 115.85 yen, up 0.1 percent. (Reporting by Tokyo markets team; Editing by Eric Meijer)