White House officials said on Friday that US President Obama believes the efforts made by US Secretary of State John Kerry may be reaching their limits, the Washington Post reported. Still, officials say, Kerry has shown no signs of backing away, staying true to a heartening phrase he often quotes, “Don’t be afraid to be caught trying."The comments come after the peace talks fell into crisis following the Israeli decision to delay the fourth agreed-upon prisoner release when the PA stated that it would not make a commitment to extending negotiations past the April deadline following the release of prisoners. Before the crisis reached its climax, Kerry discussed the strained Israeli-Palestinian negotiations with Obama last Friday in a meeting while the US president visited Saudi Arabia, and made it clear that Kerry still has a free rein to make his own decisions about what to say and do with regards to the negotiations.However, a White House official also stated that, “If he goes too far, there’s the risk of looking desperate,” adding that the time may have come for Kerry to "lower the volume."Asked whether Kerry was trying too hard, US Deputy National Security Adviser Benjamin J. Rhodes told the Washington Post that,“There is no limit to the need to work with the Israelis and the Palestinians on this set of issues... There is always going to be a reason to engage.”Rhodes added that the bigger question was "how does this impact other things that we are doing? If anything, Kerry has shown himself to be tireless, and still able to be fully invested in dealing with Ukraine, the Iran talks and other issues. There is an inevitable question of whether he is able to do this and the other things on his plate.” “Thus far, in part because of his seemingly endless reservoir of energy and frequent-flier miles, Kerry has pulled it off," Rhodes said. The US concerns were raised after Kerry, in a last ditch effort to save the peace talks, made a proposal on Tuesday that would have had Washington free Israeli spy Jonathan Pollard, Israel release the final batch of 26 Palestinians convicted of terrorist acts before the 1993 Oslo Accords, plus another 400 Palestinian prisoners “without blood on their hands,” and make commitment to a partial settlement freeze in exchange for a continuation of talks for another nine months and a Palestinian commitment not to apply to international organizations. Israel had reportedly agreed to the proposal which left Kerry to convince Abbas.But hours before US Secretary of State John Kerry was to meet with Palestinian Authority President Mahmoud Abbas in Ramallah about the deal, the latter demonstratively signed documents applying for admission into 15 treaties and conventions. Kerry canceled his trip, and the process went into a downward spin.