Hungary has erected a barbed-wire barrier along 41 kilometres of its border with Croatia in order to try and stem a flow of refugees and migrants, a defence ministry spokesman said on Saturday.

"The fence was finished overnight Friday," Attila Kovacs told AFP. The Drava River, which is difficult to cross, cuts through the remaining 330 kilometres of the border between Hungary and Croatia.

The move comes less than a week after Hungary closed its border with Serbia, sending tens of thousands of refugees and migrants into neighbouring Croatia, from where they have sought alternative routes into Europe. More than 20,000 have now entered in just three days, Croatian authorities said. Initial estimates said that that number could be expected within the first two weeks.

20,737 #refugees entered Croatia by 11am. 2,500 of them are currently in Tovarnik. #refugeescrisis — Vlada Republike Hrvatske (@VladaRH) September 19, 2015

Journalists on the ground have queried the Hungarian claims on its border barrier.

"It took Hungary weeks to build a fence with Serbia, so there is no way that they could have covered the whole [Croatia] border in just two days," Natasa Bozic, a journalist with RTL TV who has been covering the crisis, told Middle East Eye.

"The information [about Hungary building a wire fence] is inaccurate."

Croatia initially pledged free passage to the refugees earlier this week but then closed some of its border crossings with Serbia in an attempt to stop the influx, saying that it could no longer cope. Thousands still entered through informal border crossings and began to try to head north to Hungary, from where they hoped to make it on to northern Europe and places like Germany and Sweden.

Croatia responded on Friday by busing hundreds of people to the border.

"So far 22,000 people have come through in three days," said Bozic. "Before when you asked refugees they would often not even know where Croatia was, so yes the government was surprised that this many came so quickly. It is two times [the numbers] we were seeing on the Serbia-Macedonia border.

"Given the numbers we have seen, the Croatian government has responded well and has been pretty well organised about it all. There are now 40 to 50 buses ferrying people to the border. The border is large and there are no real natural barriers for people to cross, so it is pretty easy to pass through, especially now that the authorities are involved. They are taking people to places they know they can get through. There are simply not enough Hungarian police to partol all of Hungary's borders."

Prime Minister Zoran Milanovic on Saturday said that Croatia would "force" Hungary to take more people and would continue to take them to the border. This sparked stern criticism from Budapest, which said Croatia was encouraging people to enter. Tensions since then appear to have died down, with Hungary now reportedly bussing people from Croatia to Austria.

"[Prime Minister] Milanovic has said that Germany was the first to break Schengen [that is, the rules covering the passport-free travel area in Europe]. So if they [the Germans] are not going to enforce it, why should other states," said Bozic. Under the Dublin Regulations on the documentation of refugees arriving in the EU, "all of the asylum seekers must be registered in Greece and that is not happening. So we need to look at the situation in Greece, but I think at the moment the attitude is very much one of every country being out for itself."

Tensions reached a critical point on Friday when Hungarian authorities said that they had seized a train bringing refugees into the country. They then documented the new arrivals and also reportedly disarmed 40 police who were accompanying the train, the head of the Hungarian disaster unit said.

"A very serious border incident has happened because a train arrived in Magyarboly, which had more than a thousand onboard, without any warning and was accompanied by 40 Croatian policemen into Hungarian territory without any prior notice and permit, which is a very serious border violation and there are suspicions of crimes,” Gyorgy Bakondi told media.

"An investigation is under way into this. The driver of the train has been arrested, and my Hungarian colleagues have taken action in relation to the 40 Croatian policemen."

Croatian police initially denied this, saying that they had permission and that its policemen were not stripped of their weapons, but Prime Minister Zoran Milanovic has since admitted that his government did not get permission. He also added that Croatia would keep sending buses to the border to help the refugees get further into the EU.

#Croatia PM Milanovic on train issue: There was no deal with #Hungary. #Refugees wanted to go westward, so we forced Hungary to accept them. — Hrvoje Kresic (@hkresic) September 19, 2015

Under the EU's Dublin Regulations, all asylum seekers must be fingerprinted and registered in the first EU country they enter. The sheer influx of people this year though, with asylum applications up by 85 percent since last year, has seen the system all but collapse.

"I was well off in my land, I spent $10,000 to bring my whole family here, and it looks like I have to justify the reasons that led to my decission," an Iraqi who recently arrived in Croatia told Francesca Mannocchi, who is reporting for MEE from the border town of Tovarnik, where some 2,000 refugees and migrants are waiting for transportation.

"We do not want handouts. We want you to understand that in Baghdad I had a good job and a nice house, and now I'm forcing my children to sleep on the cement because I do not want that one day somebody cuts their heads off in a square," he said, adding that he was fleeing from the Islamic State group.

The EU’s data agency on Wednesday said there were 213,000 first-time asylum seekers in the EU between April and June of this year.

The number of Syrians and Afghans rose considerably, to reach almost 44,000 and 27,000 respectively, while 13,900 asylum seekers came from Iraq. A further 17,700 claims were made by Albanians, despite there being no war or serious civil unrest there.

“We need to stop the flow, we need to get reassurances from [the] European Union [about] what happens to these people who are already in Croatia, and those who still want to transit through Croatia further,” Croatian President Kolinda Grabar Kitarovic told AP.