Speaking to journalists aboard the plane returning from Malta, Francis also repeated that he was ready to make a trip to the Ukrainian capital, Kyiv, but added that he had yet to decide if it would be feasible.

"I would like to express my condolences for your fallen colleagues, whatever side they were from," he said.

"Your job is a job for the common good. They have fallen in service of the common good of information. Let's not forget that they were courageous. I pray for them, I pray that the Lord rewards their work."

At least six journalists have now died since Russian forces invaded Ukraine in late February.

Francis said he was also getting information on Ukraine in telephone contacts every few days with Rome-based Argentine journalist Elisabetta Piqué, a personal friend who has been covering the war from the start.

On his way to Malta on Saturday Francis said a trip to Kyiv was "on the table".

He said he had spoken twice to Ukrainian President Volodymyr Zelensky since the war started but indicated that the last time he had spoken with Russian President Vladimir Putin was at the start of the year.

In a speech on Saturday, Francis implicitly criticized Putin over the invasion, saying a "potentate" was fomenting conflict for nationalist interests.

Francis has strongly condemned what he has called an "unjustified aggression" and denounced "atrocities" but he has only referred to Russia directly in prayers, such as during a special global event for peace on March 25.

He said he would like to meet this year with Patriarch Kirill of the Russian Orthodox Church, whose support for the war has split the worldwide Orthodox community.

Francis stood for about 20 minutes speaking to journalists while on the plane and did not appear to be in any discomfort.

 

Migration debate

The pope said countries should always help those trying to survive "amid the waves of the sea" as he wrapped up a trip to Malta, which is at the heart of Europe's migration debate.

At the start of the last day of his trip to the Mediterranean island, Francis visited the grotto in the town of Rabat. According to tradition, St. Paul lived there for two months after he was among 75 people shipwrecked on their way to Rome in the year 60 AD. The Bible says they received unusual kindness.

"No one knew their names, their place of birth or their social status; they knew only one thing: that these were people in need of help," the pope said in a prayer in the grotto.

The 85-year-old pontiff is suffering from a flare-up of leg pain and had difficulty walking in the small grotto. At a Mass for about 20,000 people afterwards, he mostly sat while Valletta Archbishop Charles Scicluna led much of the liturgy.

Francis had to use a lift to board his flight in Rome and disembark on arrival in Valletta on Saturday, and at the end of Sunday's Mass, he skipped the traditional exit procession with all the bishops.

Malta is one of the more important routes used by migrants who cross from Libya to Europe.

The government of Prime Minister Robert Abela insists that the island, by far Europe’s most densely populated country, is "full up", refusing to allow the disembarkation of migrants other than those rescued within its own rescue zone.

Francis' last stop was a visit to a center for migrants, known as a "peace lab". There, he heard Daniel, a Nigerian, tell of his several attempts to reach Europe in unseaworthy boats and how he was detained in Libya, Tunisia and Malta.