The Belgium terror attacks: Complete coverage

A series of deadly explosions rocked Belgium's capital on Tuesday, targeting the main airport of Zaventem and the city's metro system.

Read on for CNBC's complete coverage.

Blasts at Brussels airport, subway reignite terror fears

At least 34 people have been killed in bombings at the Zaventem airport and the Maelbeek metro station that took place on Tuesday.

Police issued a wanted notice for a possible suspect, issuing a photo of a man dressed in white, wearing a hat and pushing a luggage cart.

ISIS Promises 'Dark Days' For Countries Against It

The Islamic State group has issued an updated communique taking credit for the Brussels attacks and threatening other countries taking part in the anti-ISIS coalition.

After Brussels, Europe's intelligence woes revealed

Europe must improve the regional sharing of intelligence to successfully combat the rise of homegrown militants, policy experts told CNBC a day after deadly explosions hit Brussels.

Why still terror risk, after all that security money spent?

As a result of the 9/11 attacks, $650 billion has been spent on homeland security to, among other things, beef up protection at sites such as airports, train stations, sports stadiums and other places that draw large crowds. But are we really safer or more vigilant?

Terror attacks don't necessarily rattle markets anymore

Tuesday's terror attacks in Brussels were a grim reminder of our cities' vulnerability in the age of global travel. But there's evidence that investors have become inured to their effects as attacks in the West become more common.

'Shocking level of unpreparedness' in Belgium: Experts

Current and former U.S. and European counter-terrorism officials, who are experts on ISIS in Europe, told NBC News that the location and timing of the attacks — just days after the capture of the suspected operational leader of the Bataclan massacre in Paris — suggested a "shocking" level of unpreparedness by Belgian authorities.

Terror threat looms across the world

CNBC takes a look at the threat posed by Islamist jihadist groups to countries and regions around the world.

US issues Europe travel alert

The U.S. State Department Tuesday issued a travel alert for citizens travelling to Europe following Tuesday's attacks.

The travel alert, which expires on June 20, advised U.S. citizens to exercise vigilance when in public places or using public transportation.

Why is this neighborhood home to so many terrorists?

Tuesday's explosions at Brussels airport and on the subway network will turn the spotlight on the Belgian capital's Molenbeek suburb — which has long been a hotbed of Islamist extremism. Paris attacks suspect Salah Abdeslam was also nabbed there on Friday. In November, NBC News took a look at the neighborhood.

We won't win war on terror: Former French PM

Europe is taking the wrong approach to fighting terrorism, former French Prime Minister Dominique de Villepin has told CNBC.

Speaking immediately after a series of explosions rocked the Belgian capital of Brussels, de Villepin said that they were "tragic events" but added that Europe should be showing that it is sticking to its rule of law and can only "reduce" the threat of terrorism.

Donald Trump: Waterboarding fine for terror suspects

Donald Trump said Tuesday that authorities interrogating suspected Paris terror suspect Salah Abdeslam should "do whatever they have to do" to get information in light of the deadly attacks in Belgium.

Trump said on NBC's "TODAY" if he were elected president he would make sure the United States has "strong borders," and said people looking to come into the country would need "absolute perfect documentation."

Travel industry reacts to Brussels attacks

The travel industry is trying to reassure customers following deadly attacks in Brussels' main airport and metro system.

New York tightens security after Brussels bombings

Police in New York will visibly increase their presence at airports and train stations after Tuesday's bombings in Brussels, authorities told NBC News.

Brussels attack could affect cross-border commerce, Brexit

The attacks in the Belgian capital on Tuesday are unlikely to have a long-term impact on markets, but they could result in new roadblocks to cross-border commerce and lend momentum to Euro sceptics, analysts told CNBC.

European stocks were under pressure but had come off their lows following deadly attacks at Brussels main airport and on the city's metro system.

Facebook activates safety check feature after Brussels attacks

Facebook activated its Safety Check feature Tuesday morning, following explosions around Brussels. The option allows users in a tragedy or natural disaster to mark themselves as safe, and was widely used — and praised — after the Paris shootings attacks last November.

Brussels Airport was the scene of at least two explosions Tuesday morning, with another blast at a nearby subway station. The threat level in Brussels has been raised to high, all public transport has been shut down and residents have been advised to stay home.

Brussels attacks: World leaders condemn 'deplorable' terror attacks

World leaders took to Twitter to condemn the attacks in Brussels while sending their condolences to the victims and solidarity with Belgium.

These sectors will be sold off following Brussels attacks

Stocks in the tourism sector fell Tuesday as a result of the terror attacks in Brussels, but the decline will only be short term, according to investment experts.

The Euro Stoxx 600 travel and leisure sector slipped 1.9 percent by Tuesday midday and was the worst performer across the regional benchmarks. Ryanair shares fell 2.9 percent, Air France shares lost 4 percent and IAG was down 2.5 percent. This came as major airlines cancelled flights from Brussels after the blasts.

Kensho Trade: Terror fears exit market quickly

U.S. and European stocks traded lower in early Tuesday trading after terror attacks in Belgium's capital. A tough, but necessary reality for traders on Wall Street is that they need to adjust their asset allocation on these tragic events.

How has the market traded in the wake of such attacks in the near and long term?

Social media reacts to terror attacks in Belgium

A series of deadly explosions rocked Belgium's capital Tuesday, targeting the main airport of Zaventem and the city's metro system.

Belgian Prime Minister Charles Michel told a news conference that terrorists had committed murder, labeling it a cowardly attack and calling it a black day for the country.

CNBC has compiled tweets from within Brussels and around the world reacting to the deadly attacks.

Manhunt for surviving Brussels bomber

Belgian authorities have launched a massive manhunt for Najim Laachraoui, the only surviving prime suspect in Tuesday's Brussels bombings.

Must Europe give up freedoms for security?

Civil liberties and human rights are key pillars of the European Union but after yet another terrorist attack in a European capital, questions are being asked over whether the bloc needs to restrict freedoms amid the heightened terrorist threat.

Airport security in spotlight after Brussels attacks

Several countries have tightened or reviewed airport security following twin explosions at Brussels Airport, as Australian Prime Minister Malcolm Turnbull on Wednesday blamed Europe's porous borders and lax security for the attack.

After Brussels, Europe's intelligence woes revealed

Europe must improve the regional sharing of intelligence to successfully combat the rise of homegrown militants, policy experts told CNBC a day after deadly explosions hit Brussels.

Ex-CIA officer: Do THIS to root out terror

The U.S. lacks the political will to really do what it takes to stop terrorism, Rep. Will Hurd, a former undercover CIA operative, tells CNBC.

Georgian Public Broadcaster | AP

Scenes from the Brussels attacks

CNBC has put together a series of pictures, from within Brussels and around the world, depicting reactions to the horror.