The Vatican ambassador to the Holy Land on Tuesday expressed frustration over the decade-old failure to reach an agreement with Israel on tax exemptions, amid mounting criticism among senior Vatican officials on the state of relations between the Jewish state and the Holy See. "Some kind of frustration can be felt, because it takes so long time to reach [an] agreement," Monsignor Antonio Franco told The Jerusalem Post. "Feelings of disappointment are natural." His comments came on the heels of remarks by his predecessor, Archbishop Pietro Sambi, who described Vatican-Israeli relations as worsening as a result of a failure to reach agreement on critical issues such as tax exemptions and travel restrictions. "We have problems dealing with these issues and hope that they can be resolved as soon as possible," Franco said. Franco, who replaced Sambi as papal envoy to Israel a year ago, said it was not only Sambi who was critical of the current state of relations, adding that an increase in monthly negotiating sessions was needed to resolve the prickly issues. The negotiations between the two sides are scheduled to resume on December 12. The Vatican established diplomatic relations with Israel in 1993, but the key issue of taxation was left unresolved, with the failure to reach an accord on the issue more than a decade later casting a pall on relations. Rabbi David Rosen, who helped negotiate the basic agreement between the two sides 14 years ago, said the relationship remains strong, despite Israel's failure to keep key promises to the Vatican, including issues of taxation. "The Vatican is showing remarkable patience and understanding regarding commitments made by the State of Israel in the Fundamental Agreement, which were to be resolved within two years but which have still not been resolved," said Rosen, who is in charge of interfaith relations at the American Jewish Committee. He added that this patience on the part of the Vatican was a testimony to their commitment to good relations with the Jewish People and the State of Israel. At the core of the dispute is hundreds of millions of shekels in overdue property tax that the Vatican and an array of Christian churches in Jerusalem owe the city. According to law, properties that are used as houses of prayer are exempt from paying property tax, or arnona. But the churches, which own a vast number of properties in Jerusalem, are required to pay the city property tax for buildings they own that are not used for worship, including hostels, guest houses and schools, the city said. The total amount of unpaid property tax amounts to roughly NIS 300 million, with the Latin Patriarchate the biggest offender, a city spokesman said. The debt collection has been frozen pending ongoing negotiations between the State of Israel and the Vatican over the delicate issue. The Vatican is said to be willing to pay only a symbolic fee for the city services they receive. Any agreement reached between the State of Israel and the Vatican would then apply to all the various church properties in Jerusalem. A secondary issue between the two sides has to do with the legal structure of church authority in the Holy Land, which has been agreed upon but never confirmed by the Knesset. An additional sore point is the travel restrictions on Arab clergy traveling from the West Bank, which Israel intermittently imposes due to security considerations. An Israeli Foreign Ministry official on Tuesday expressed surprise over the recent Vatican criticisms in light of the "major progress" that has been made between the two sides in negotiations over the last two years. Earlier this year, the Vatican Ambassador to Israel created a diplomatic firestorm after threatening to boycott the annual Holocaust Remembrance Day state ceremony at Yad Vashem because of a caption at the Holocaust Museum referring to the silence of Pope Pius XII during the murder of six million Jews in the Holocaust. The Vatican is pressing ahead with its plans to beatify the wartime pope over the objection of the State of Israel and Jewish groups around the world.