VALLETTA, June 28 (Xinhua) -- The Maltese government said Thursday that it would be closing the country's ports to NGO-operated migrant vessels, pending the outcome of an investigation into the case of the MV Lifeline.

The decision was announced as European leaders converged in Brussels for an EU summit in which migration will be at the top of the agenda.

The vessel MV Lifeline was at the center of an international dispute after it rescued over 200 migrants from within the Libyan search and rescue area last Thursday.

In the ensuing standoff, it emerged that despite flying a Dutch flag, the ship was only registered as a pleasure craft, with the Netherlands claiming that it had no knowledge of the ship.

MV Lifeline was allowed to berth in Malta on Wednesday after an agreement was reached that will see the migrants that were on board distributed among nine countries.

An investigation has been launched into the vessel's operations.

In a statement issued on Thursday evening, the Maltese government said that following recent events that had brought "previously unknown" information to the fore, the country needed to take stock of the situation.

"Malta needs to ascertain that operations being conducted by entities using its port services and operating within the area of Maltese responsibility are in accordance with national and international rules," the government said.

"Given that there are investigations being carried out by independent authorities, and until these issues are clarified, Malta cannot allow entities ... to make use of Malta as their port of operations," the statement read.