Migrants in distress at sea have told their rescuers that several ships passed them by without offering assistance, a European aid group said yesterday while seeking safe harbor for a rescue vessel with 141 migrants aboard.

SOS Mediterranée said that due to the recent refusal of Italy and Malta to let rescue vessels carrying migrants dock, ships might be now unwilling to do rescues "due to the high risk of being stranded and denied a place of safety."

Two French groups operating the rescue ship Aquarius said Saturday it was back in Libyan coastal waters for the first time since triggering a diplomatic row over migration in June. The Aquarius picked up 141 people on Friday in two separate operations, SOS Mediterranée and Doctors Without Borders said on Twitter. The Aquarius "remains in the search and rescue zone, and on the lookout for any other craft in distress."

In June, Aquarius was forced to sail north for days with more than 600 migrants to Spain after Italy and Malta refused it docking permission. Since then, other private rescue vessels have had to wait for days until some country agreed to let migrants disembark.

Italy's new populist government has vowed that no more private aid ships will bring migrants to Italian shores. Although arrivals in Italy of rescued migrants smuggled from Libya have sharply dropped off this year compared to previous years, some 600,000 reached Italian ports in the last few years. Italy demands fellow European Union countries take the asylum-seekers from Africa, Asia and the Middle East. The tiny EU island nation of Malta says it can't handle large numbers of migrants.

Cargo and other commercial vessels often have plucked migrants to safety from deflating rubber dinghies and rickety wooden boats. But with Italy's crackdown, commercial ships risk being blocked for days at sea, unable to carry out their business. Recently a support ship for an offshore oil platform was left in limbo for days after rescuing migrants.