Updated 8.10pm with Italy's latest reaction

Italy's right-wing government has accused Malta of refusing a rescue boat packed with 239 migrants, describing its decision on Friday night as "inhumane".

Transport minister Danilo Toninelli fired the latest broadside at Malta, hours after deputy prime minister Matteo Salvini told Malta to take in a boat of migrants that Italy refused to host, and to arrest its crew.

Mr Toninelli criticised Malta on his Facebook page, where he also posted a photo of an email full of nautical information and signed by the Armed Forces of Malta inferring that it was not responsible for the latest ship as it was not in a "SAR (Search and Rescue) Situation".

Home Affairs Minister Michael Farrugia shot back with a statement saying "Toninelli should stick to the facts."

The boat at the centre of the controversy is a Dutch-flagged ship run by German charity Mission Lifeline.

On Friday afternoon, a Spanish government spokeswoman said Spain has been in contact with Malta to offer humanitarian help with the ship, though details remain sketchy.

"We have been in contact with Malta to offer support if humanitarian help is needed by the boat in the next few hours," government spokeswoman Isabel Celaa said during a news conference following the weekly cabinet meeting.

The Lifeline is now in Maltese waters sparking another diplomatic row before EU leaders meet on Sunday to discuss the migration dilemma. 

"For the safety of the crew and passenger safety we have requested that Malta open the ports. It is clear that then that ship will have to be seized, and its crew stopped," Salvini said in a tweet.

But sources said even though the vessel had entered Malta's search and rescue area it had not received a request for assistance from either the Rome coordination centre or the ship captain. No distress call has been made so far.

Italy appeared to relent on Thursday night after at first refusing to accept the migrants on board a German charity rescue ship, saying later in the day it would take them in but would impound the vessel.

The Italian government initially said the Dutch-flagged vessel should take the people it had plucked from the Mediterranean to the Netherlands, not Italy. But transport minister Danilo Toninelli, who oversees the coastguard, later said it was unsafe for the 32-metre vessel to travel so far with so many people on board. 

Matteo Salvini has upped his migration rhetoric.

It has since made its way into Malta's search and rescue area. The condition of those on board is not yet known and questions sent to the NGO remained unanswered.

A Maltese government spokesman said that according to the Rome coordination centre, the search and rescue took place between Libya and Lampedusa. The operation was initially handled by MRCC Rome, with the Libyan authority assuming responsibility of the SAR cases.

Sources told Times of Malta that the Rome coordination centre called their Libyan counterparts to intervene on Thursday but there was no reply. 

"In these cases, Malta was neither the coordinating nor the competent authority," the spokesman said. 

It transpires that Lifeline "breached its obligations" to abide by instructions given to it by the competent search and rescue authorities in this case, namely the Libyan coastguard or Italian coastguard, the government added. 

In a diplomatic tone, the Maltese government added: "we will always continue to act according to the laws and applicable conventions". 

A Spanish government spokesman said on Friday afternoon that contact had been made with the Maltese, Italian and French governments about the latest saga.

The NGO Mission Lifeline incensed the Italian deputy prime minister last week when it tweeted in reaction to one of his Facebook posts: "When fascists promote us..."

An irritated Salvini tweeted back, saying “insults and threats will not stop us” and that Italians would run their own country.

The Lifeline said it was sailing under a Dutch flag but it was not on the official Dutch register because it was a smaller ship.

Earlier this month Salvini pledged to no longer let charity ships bring rescued migrants in Italy, leaving the Gibraltar-flagged Aquarius stranded at sea for days with more than 600 migrants until Spain offered them safe haven.

Read: Malta ‘unprepared’ for influx of migrants, OPM sources concede

Off the Libyan coast, where people smugglers operate with impunity, the UN refugee agency said an estimated 220 migrants drowned this week. The death toll in the central Mediterranean this year is nearing 1,000, the UNHCR said.

All EU must help migrant recipient countries - Commissioner

Meanwhile, European Commissioner Guenther Oettinger said on Friday that all European Union countries need to help southern neighbours, where most migrants are arriving.

Oettinger told reporters in Luxembourg on Friday that the Sunday meeting should serve as a "a reminder of the way towards European unity".

"I think that the whole of Europe must show solidarity towards those who are most affected, the Greeks, Malta, Cyprus, Bulgaria, Italy and Spain, to ease their burden and to reimburse and honour a part of their costs and efforts," he said.