U.S. President Joe Biden is a “strong supporter” of NATO, and the alliance can be further strengthened with him in office, NATO’s Secretary-General Jens Stoltenberg said this week.

“President Biden and the inauguration of him as the new president represents a new chapter for our alliance because Joe Biden is such a strong supporter of NATO. He knows NATO very well,” the NATO chief told CNBC’s Hadley Gamble on Thursday.

This will be an opportunity to further strengthen NATO, he added, noting that Biden wants to rebuild alliances.

U.S. commitment to NATO reached a low point under former President Donald Trump. He repeatedly attacked allies for paying less than their fair share toward the group.

Stoltenberg said he looks forward to working with the new administration to address issues around the world.

“We are faced with so many challenges at the same time: the rise of China, the … shift in the global balance of power, a more assertive Russia using force against neighbors in Ukraine and elsewhere, and then, of course, the constant threat of terrorist attacks,” he said.

“None of us can tackle this alone, we have to stand together,” he said. “I don’t believe in America alone, I don’t believe in Europe alone, I believe in Europe and North America together in NATO.”

The Pentagon last week announced that the number of U.S. troops in both countries has been reduced to 2,500, as directed by Trump when he was president.

His administration signed an agreement with the Taliban in February that aims for a permanent ceasefire in Afghanistan and would reduce American military presence in the country.

NATO also has personnel in Afghanistan and Iraq.

Stoltenberg said NATO is in close consultation with the new U.S. administration. “We will face a difficult dilemma,” he said.

Leaving would risk losing the gains made in Afghanistan in fighting international terrorism and making social progress, but staying means continued involvement in a “difficult military conflict.”

“What matters for me is that we make decisions together, that we are coordinating everything we do in Afghanistan,” he said.

NATO plans to expand its presence in Iraq, Stoltenberg added.

“I strongly believe that the best way we can help to prevent ISIS terrorists from returning is by training the Iraqi forces, help them to fight the terrorists themselves,” he said.

— CNBC’s Matt Clinch contributed to this report.

LONDON — Business activity in the euro zone fell to a two-month low in January, preliminary data showed on Friday, on the back of stricter coronavirus-related lockdowns.

The region is grappling with growing Covid-19 infection rates and tighter restrictions as new strains of the virus spread, causing further economic pain.

Markit’s flash composite PMI for the euro zone, which looks at activity across both manufacturing and services, dropped to 47.5 January, versus 49.1 in December. A reading below 50 represents a contraction in activity.

Chris Williamson, chief business economist at IHS Markit, said a double-dip recession for the euro zone was looking “increasingly inevitable.”

“Tighter COVID19 restrictions took a further toll on businesses in January,” he said in a statement.

“Output fell at an increased rate, led by worsening conditions in the service sector and a weakening of manufacturing growth to the lowest seen so far in the sector’s seven-month recovery.”

European Central Bank President Christine Lagarde acknowledged on Thursday that the pandemic still posed “serious risks” to the euro zone economy.

In addition to the new Covid variants, there are also concerns over a slow vaccination roll-out across the European Union.

“In this environment ample monetary stimulus remains essential,” Lagarde said. The ECB decided at a meeting on Thursday to keep interest rates and its wider stimulus programs unchanged for now, having boosted its support in December.

The ECB expects the euro zone’s GDP (gross domestic product) to expand by 3.9% in 2021, and 2.1% in 2022. This is after a contraction of 7.3% last year. However, these forecasts are dependent on the evolution of the pandemic.