Pope Francis' respiratory tract infection is presenting a "complex clinical picture" that will require further hospitalization, the Vatican said Monday as concerns grew about the increasingly frail health of the 88-year-old pontiff.

Vatican spokesman Matteo Bruni said the results of tests conducted in recent days and Monday indicate the pope is suffering from a "polymicrobial respiratory tract infection" that has necessitated a further change in his drug therapy. Scientists say polymicrobial diseases are caused by a mix of viruses, bacteria, fungi and parasites.

Japan's economy grew at a better-than-expected annual rate of 2.8% in October-December, underlined by steady exports and moderate consumption.

On a quarter-to-quarter basis, the world's fourth largest economy grew 0.7% for its third straight quarter of growth, the Cabinet Office reported Monday in its preliminary data.

The mineral ilmenite is extracted from mounds of sand deep in the earth and refined using a method that summons the force of gravity, resulting in a substance that glimmers like a moonlit sky.

Ukraine boasts vast reserves of ilmenite — a key element used to produce titanium — in the heavy mineral sands that stretch for miles along the country's embattled east.

Global shares traded mixed on Monday as investors continued to watch economic data and policy moves from U.S. President Donald Trump, as both are likely to impact upcoming central bank moves.

France's CAC 40 dipped nearly 0.1% in early trading to 8,171.59, while Germany's DAX added 0.4% to 22,560.00. Britain's FTSE 100 edged up 0.1% to 8,742.97.

Russia has freed a U.S. citizen arrested earlier this month on drug smuggling charges, according to Russian media reports and a U.S. official.

The move appears to be an effort to ease tensions between Moscow and Washington ahead of talks in Saudi Arabia on Tuesday.

China's President Xi Jinping met with private sector business leaders on Monday, offering them assurances that policies regarding the private sector would not change, state media reported, as government officials work to revive an economy disrupted by a pandemic, regulatory crackdowns and a real estate crisis.

Among those present was Alibaba founder Jack Ma, who was part of a focus on a crackdown on the tech industry in recent years.

When Hamas threatened to call off the planned release of three Israeli hostages last week, U.S. President Donald Trump stepped into the picture with an unexpected ultimatum.

Speaking in the Oval Office, Trump called on Hamas to release all of the more than 70 hostages it is holding by noon on Saturday. Otherwise, he warned, "all hell is going to break loose."

Germany hasn't seen significant economic growth in five years. It's a stunning turnaround for Europe's biggest economy, which for much of this century had expanded exports and dominated world trade in engineered products like industrial machinery and luxury cars.

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Harsh weather moved west on Monday as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend, killing at least 10 people, including nine victims in Kentucky who died during flooding from heavy rains.

The National Weather Service warned of "life-threatening cold" into Tuesday, with temperatures in northeastern Montana predicted to dip as low as 45 degrees below zero (-42.7 degrees Celsius) with wind chills down to 60 below (-51 degrees Celsius).

Paul Simon and Sabrina Carpenter duetted on Simon's "Homeward Bound" to open the show, five-decade "Saturday Night Live" luminary Steve Martin delivered the monologue, and Paul McCartney gave an epic closing to a 50th anniversary special celebrating the sketch institution that was overflowing with famous former cast members, superstar hosts and legendary guests.

The 83-year-old Simon has been essential to "SNL" since its earliest episodes in 1975, and told the 25-year-old pop sensation of the moment Carpenter that he first performed "Homeward Bound" on "SNL" in 1976.