Thousands of men, women and children -- many fleeing conflict in Syria or Afghanistan -- are on the move toward northern Europe, where they hope to claim asylum in European Union countries such as Germany.
The mass movement of people has led to tensions in non-EU countries on their route, including Macedonia
Hungary, which is in the EU, has already announced stepped-up security measures to prevent migrants entering, including building a temporary barrier along the border with Serbia.
Justice Minister Laszlo Trocsanyi told Hungarian media Tuesday that the influx of migrants "has created an emergency situation in the region" and that "having 1,500 people entering the country illegally on a daily basis is unacceptable," according to the government's website.
State Secretary of Justice Robert Repassy said procedures for handling migrants would also be made faster and more efficient.
'Fraught with dangers'
A report that rights group Amnesty International released last month
said the western Balkans route had overtaken the Mediterranean to become the busiest irregular passage to the EU.
The number of people stopped crossing the Serbia-Hungary border alone has risen by more than 2,500% since 2010, it said, from 2,370 to just over 60,600.
"The route which takes refugees and migrants by sea from Turkey to Greece and then over land across Macedonia to Serbia and into Hungary is less deadly than the sea crossing from Libya, but it is still fraught with dangers and obstacles," Amnesty International said.
The group is critical of how the authorities in Hungary, Serbia and Macedonia are handling the wave of migrants but adds that the current situation is the result of "a broader failure of EU migration and asylum policy."
Despite the risks, thousands of migrants continue to make the perilous journey by sea from Libya, many bound for Italy's Mediterranean islands.
In the latest tragedy, the bodies of 50 migrants were found Wednesday in the hull of a large ship rescued by the Swedish coast guard, operating on behalf of the EU border agency in the Mediterranean Sea, according to the Italian coast guard, which coordinated the operation.
The vessel had 439 surviving migrants on board, the Italian coast guard spokesman said. It is unclear where the survivors will be taken.
It's not yet known what caused the deaths, but in the past migrants trapped on the lower decks of vessels have died of asphyxiation or been poisoned by the fumes from leaking engines.
Earlier, the Italian coast guard said it had picked up 120 migrants --, including two children and 17 women, five of whom were pregnant -- from a rubber dinghy about 65 kilometers (40 miles) off the Libyan coast. They were taken to the Italian island of Lampedusa.
'Unprecedented pressure on border control authorities'
EU border agency Frontex said last week that the number of migrants detected at EU borders had more than tripled to 107,500 in July, compared with the same month last year.
It's the first time the total has passed 100,000 for a single month since Frontex began keeping records in 2008, it said. The previous monthly high was 70,000 in June.
The huge influx in July brings the number for the seven months from January to July to nearly 340,000, compared with 123,500 recorded in the same period of last year and 280,000 in all of 2014, the agency said in a statement.
"This has created an unprecedented pressure on border control authorities in Greece, Italy and Hungary," Frontex said.
"Syrians and Afghans accounted for a lion's share of the record number of migrants entering the EU illegally. Most of them, fleeing instability in their home countries, initially entered Greece from Turkey."
Germany's government said last week that it expected up to 800,000 asylum seekers to come this year -- four times more than in 2014.
Not all Germans are happy about their country's willingness to take in those in need.
German Chancellor Angela Merkel visited a refugee shelter Wednesday in the eastern German city of Heidenau, where dozens of police officers were injured in weekend clashes with right-wing protesters, according to German media reports