Authorities in Europe have tightened security at airports, on subways, at the borders and on city streets after deadly attacks on the Brussels airport and its subway system.

The Paris airport authority said security was tightened at all Paris airports soon after the Brussels explosions on Tuesday morning.

Airports in London, Prague, Amsterdam, Vienna, and many others, also saw increased security.

The attacks come just days after the main suspect in the November 13 Paris attacks was arrested in Brussels on Friday.

In Moscow, Russian Transport Minister Maxim Sokolov told Russian news agencies that authorities will “re-evaluate security” at Russian airports, although its measures are already among some of the toughest across Europe.

There have been mandatory checks at the entrances to airports since a 2011 suicide bombing at Moscow’s Domodedovo airport that killed 37.

Gatwick airport said that “as a result of the terrible incidents in Brussels we have increased our security presence and patrols around the airport”.

Heathrow said it was working with police to provide a “high-visibility” presence in light of the attacks.

In Germany, the state rail system, Deutsche Bahn, has halted its high-speed rail service from Germany to Brussels. The company said its ICE trains are now stopping at the border city of Aachen.

The British, Dutch and Polish governments convened emergency meetings as they beefed up security at airports.

Dutch Prime Minister Mark Rutte and Britain’s David Cameron vowed to help Belgium.

“Our thoughts are there, in Brussels and we are praying for the victims,” said Polish Prime Minister Beata Szydlo, who cancelled a routine news conference to attend an emergency meeting with her government security council.

Austrian interior ministry spokesman Karl-Heinz Grundboeck said more police are on the streets and at airports in Vienna and other major Austrian cities even though there appears to be no “Austria connection”.

Spain’s interior ministry said officials were meeting to discuss the situation following the blasts in Brussels but that for the moment Spain was maintaining its Security Alert Level 4 – one step below the maximum – that has been in place since the Charlie Hebdo attacks in Paris in January 2015.

In the United States, the country’s largest cities were placed on high alert and the National Guard was called in to increase security at New York City’s two airports.

A United Nations agency is already due to review airport security following the downing of a Russian airliner in Egypt by a makeshift soda-can bomb in October last year. Islamic State has claimed responsibility for smuggling the bomb on board.

But there has been less attention focused on how airports themselves are secured, before passengers check in for flights, despite a number of attacks.

“It strikes me as strange that only half of the airport is secure. Surely the whole airport should be secure, from the minute you arrive in the car park,” said Matthew Finn, managing director of independent aviation security consultants Augmentiq.

In 2011, a suicide bomber struck the arrival hall at Moscow’s Domodedovo airport, killing 37 people. In 2013, a shooter killed a US government Transportation Security Administration officer at Los Angeles international airport.

The relative openness of airports’ public areas in Western Europe contrasts with some in Africa, the Middle East and Southeast Asia, where travellers’ documents and belongings are checked before they are allowed to enter the airport building.

In Turkey, passengers and bags are screened on entering the terminal and again after check-in. Moscow also checks people at terminal entrances.

“Two terrorists who enter the terminal area with explosive devices, this is undoubtedly a colossal failure,” Pini Schiff, the former security chief at Tel Aviv’s Ben-Gurion airport and currently the CEO of the Israel Security Association, said in an interview with Israel Radio.

But such checks could create upheaval at terminals and rely on security staff paying close attention.

“Any movement of the security ‘comb’ to the public entrance of a terminal building would cause congestion, inconvenience and flight delays, while the inevitable resulting queues would themselves present an attractive target,” said Ben Vogel, Editor, IHS Jane’s Airport Review.

But adding pre-terminal screening and other measures at airports would be costly.

“I don’t see it happening anytime soon,” said Daniel Wagner, CEO of Country Risk Solutions, a security consulting firm in Connecticut in the United States. “There’s no sense of urgency and not enough money devoted to the problem.”