BRUSSELS — The European Union authorities formally appealed to the bloc’s member states on Wednesday to accept quotas of migrants to relieve the burden on southern states like Italy and Greece that are the main landing points for them.

The proposal by the European Commission, the executive arm of the European Union based in Brussels, is a response to concern that the bloc’s southern coastal states could become overwhelmed by the inflow of migrants making the dangerous crossing of the Mediterranean Sea in often rickety and unseaworthy vessels.

The International Organization for Migration said on Wednesday that 1,840 migrants had been lost at sea or were known to have died while crossing the Mediterranean so far this year. That compares with 425 people during the same period last year.

The organization said Italy and Greece had received most of the 78,826 migrants who reached Europe this year. And while it was not able to make an exact comparison, it said arrivals in Italy over the same period last year were mostly unchanged at about 41,000. In Greece, however, there was a significant increase, with 37,000 people arriving so far this year compared with 34,000 during all of 2014.