CONSTANTA, Romania - Romania's coast guard on Wednesday rescued more than 150 migrants from Iraq and Iran, including 56 children, from a ship in distress on the Black Sea, on what is becoming a favoured route for migrants trying to reach Western Europe.

The rusty ship was towed to the Black Sea port of Constanta, some 250 kilometres (150 miles) east of Bucharest, before dawn.

Revising its initial count, the coast guard said it found 157 migrants from Iran and Iraq who had “intended to illegally enter our country.” Some migrants received medical treatment.

Authorities initially spotted the ship outside Romanian territorial waters early Tuesday. It sent a distress signal and two coast guard boats were dispatched, but high waves and winds hampered rescue efforts before the ship was eventually towed to port.

Fabian Badila, a border police spokesman, said the migrants would be taken into custody and then moved to government-run migration centres in Romania.

He said the border police had an efficient surveillance system which could detect vessels trying to illegally enter Romanian territorial waters.

Migrants are increasingly using the Black Sea route from Turkey to reach Romania. Last weekend, coast guard forces from Romania and Bulgaria intercepted 217 migrants in the Black Sea in two boats who were suspected of trying to illegally enter Romania.

Any new influx of migrants through the Black Sea could further exacerbate political strains within the European Union over the issue.

Krzysztof Borowski, a spokesman for the European Union's border agency, Frontex, told The Associated Press that smugglers are attempting to “revive the route,” which as recently as 2014 had been used by some 430 migrants. Since then the numbers have fallen as other routes via Turkey into Greece became popular. In 2015, 68 migrants used the Black Sea route, and in 2016 only one, Borowski added.

Metin Corabatir, who heads the Ankara-based Research Center on Asylum and Migration, said he believed the Black Sea was unlikely to become a major route because the sea is too rough and the period for safe crossings is very short. There are also allegations that Bulgarian, and also Romanian authorities have mistreated migrants, with reports of beatings and forced expatriations.

Romanian border police told The Associated Press illegal migration has increased this year with 4,200 cases of Afghan, Iraqi, Syrian, Pakistani and Iranian citizens trying to enter or leave Romania. That's up sharply from 2016 when there were 1,624 attempts.