But Nadav Tamir, a political adviser to Peres, said Sunday the Israeli government authorized the trip and Israeli Prime Minister Benjamin Netanyahu was in "constant contact" with Peres. Speaking on Israeli Army Radio, Tamir stressed the meeting was not political, even though he said Peres and Abbas were expected to discuss political developments when they met in private after the prayer.
Netanyahu has urged the world to shun Abbas' new unity government which took office last week because it is backed by the Islamic militant group Hamas. His pleas have been ignored by the West, with both the U.S. and the European Union saying they will give the unity government a chance.
Peres' participation thus undermined Netanyahu's attempts to isolate the Palestinians and instead added to the growing isolation of Netanyahu's hard-line position. Netanyahu's office has declined repeated requests for comment about the Vatican summit.
Peres, 90, deviated from his prepared remarks in the garden to add a personal note as his term as Israeli president comes to an end.
"I was young. Now I am old," he said. "I experienced war. I tasted peace. Never will I forget the bereaved families — parents and children — who paid the cost of war. And all my life I shall never stop to act for peace, for generations to come.
"Let's all of us join hands and make it happen," he said.
Abbas made a few political points, saying Palestinians craved peace as well as "dignified living" and "freedom in our sovereign and independent state."
"We want peace for us and for our neighbors," he said, according to his prepared text.
The two met privately for about 15 minutes inside a nearby Vatican villa.
Josef Federman and Tia Goldenberg in Jerusalem and Daniela Petroff in Vatican City contributed.
Follow Nicole Winfield at www.twitter.com/nwinfield
- Germany: Syrian asylum seekers blows himself...
- Pope Francis: The world's at war, but not a...
- Pope visits Auschwitz in silence, meets...
- Erin Stewart: Should you teach your kids to...
- President Uchtdorf visits refugees; presents...
- President Uchtdorf presents $3 million to...
- Elder LeGrand R. Curtis Jr. addresses 'A...
- First-timers and veterans among thousands to...
- Is Bernie Sanders an atheist? 44
- President Uchtdorf visits refugees;... 35
- Democrats and Republicans double-down... 31
- 'Duck Dynasty' star: Media,... 26
- Erin Stewart: Should you teach your... 22
- Defending the Faith: The 18th annual... 19
- Can Hillary Clinton finally close the... 17
- The Clean Cut: New BYU football video... 15