TOKYO (REUTERS) - US share futures and the dollar slipped in early Asian trade on Wednesday (May 17) after reports that President Donald Trump asked then-FBI director James Comey to end a probe into his former security adviser.

The reports raised questions about whether charges of obstruction of justice could be laid against Mr Trump, weakening confidence in the US President's ability to push through an aggressive stimulus programme that investors had been banking on since his election last November.

US economic data published on Tuesday was mixed after soft retail sales and inflation data on Friday, also undermining investors' optimism on the US economy.

S&P 500 mini futures, the world's most liquid stock futures, dropped 0.5 per cent in early Asian trade.

MSCI's broadest index of Asia-Pacific shares outside Japan dipped 0.1 per cent while Japan's Nikkei fell 0.6 per cent.

"Worries about European politics and North Korea have receded. The earnings are mostly over. But now we have worries about the Trump administration. Given that there are some stock indexes that have risen more than 10 per cent so far this year, we may be entering a consolidation phase," said Mr Nobuhiko Kuramochi, chief strategist at Mizuho Securities.

Mr Trump asked Mr Comey to end the agency's investigation into ties between former White House national security adviser Michael Flynn and Russia, according to a source who has seen a memo written by Mr Comey.

The news, first reported by New York Times, came after Mr Trump had fired Mr Comey and then discussed sensitive national security information about Islamic State with Russian Foreign Minister Sergei Lavrov.

The White House quickly denied the New York Times report, saying in a statement it was "not a truthful or accurate portrayal of the conversation between the president and Mr Comey."

The tumult at the White House prompted currency traders to ditch the US dollar against a broad range of currencies, most notably against the yen, which often becomes a safe-haven when there are problems in Europe and the United States.

The dollar dropped 0.5 per cent in early Asian trade to 112.59 yen, slipping further from its highs near 114.40 yen touched last week.

The dollar's index against a basket of six major currencies dropped to 98.063, essentially giving up all of its gains made after Mr Trump's election victory.

The euro held firm at US$1.1086, having hit a six-month high of US$1.10975 on Tuesday, as it also drew help from solid economic data in the euro zone.

The euro zone GDP grew 0.5 per cent in January-March, in line with expectations, and underscoring a recovery in the currency bloc.

On the other hand, US economic data published on Tuesday was mixed, raising more doubts about rosy views on the U. economy.

US manufacturing production recorded its biggest increase in more than three years in April but housing starts posted a surprise fall to five-month lows.

The data came after Friday's softer than expected retail sales and inflation.

"Until Friday, markets had been focusing only on the bright side of the US economy. But that seems to have changed," said Daisuke Uno, chief strategist at Sumitomo Mitsui Bank.

The 10-year US Treasuries yield dipped to 2.293 per cent, the lowest level in two weeks.

Oil prices dropped following data that showed an unexpected rise in US inventory. US crude futures traded at US$48.28 per barrel, down 0.8 per cent from late US levels.