ROME (AP) — The Latest on migrants trying to enter Europe (all times local):

1:45 p.m.

The United Nations refugee agency is calling on European governments to urgently allow in more than 500 people rescued in the Mediterranean but who remain stranded at sea as countries bicker over who should take them.

UNHCR special envoy Vincent Cochetel said Tuesday that "this is a race against time." He says "storms are coming and conditions are only going to get worse."

The migrants are aboard two ships chartered by humanitarian aid groups, but Italy's anti-migrant government is denying them access to its ports.

The UNHCR says nearly 600 people have died or gone missing in waters between Libya and Italy this year.

The European Commission says it's urging member countries to take action and is offering support, but has no power to intervene.

A spokeswoman says "there's nothing more we can do."

11:30 a.m.

More than 500 rescued migrants are stuck in the Mediterranean on two NGO boats, as Italy and Malta continue to deny them access to their ports.

French charity group Doctors Without Borders (MSF) said late Monday in a tweet that it had completed "a critical rescue" of another 105 people onto the Ocean Viking, raising the total number of migrants on board ship to 356.

Another 150 migrants remain on board the Spanish charity vessel, the Proactiva Open Arms.

Italy's hard-line interior minister, Matteo Salvini, reiterated Tuesday his intent on making sure the two migrant ships don't enter Italian ports.