St. Petersburg, September 5 - Premier Enrico Letta said Thursday that he could understand the United States's concerns over Syria, but reiterated Italy was only in favour of military intervention if it is endorsed by the United Nations. Letta told a press conference at the G20 summit in the Russian city of St. Petersburg that he felt an "understanding" of the American outrage towards alleged chemical weapons use by the Syrian government. However, without an endorsement of action from the United Nations, Italy is "unable" to intervene, said Letta. He also said that he noticed no "coldness" between US President Barack Obama, whose government appears close to sanctioning air strikes in Syria, and Russia's Vladimir Putin, an ally of Syrian President Bashar al-Assad. "There does not appear to be any element of coldness," said Letta.