A half-brother and sister, children of a Holocaust survivor, have found each other with help from the International Tracing Service in Germany.

Ursula, a German, and Eli, an Israeli, have never met. But they have spoken, after ITS employee Adina Horn, who helps answer queries from people searching for relatives, made the connection and put them in touch.

"Ursula was looking for her father, a Jewish survivor, and asked for help from the ITS," Ms Horn said.

Ursula's father, Nathan Ulinski, was at a displaced persons camp when he met her mother, Ruth, a non-Jewish German. They had a son, Gerhard, and Ruth was pregnant with Ursula when Nathan left them, moving to Palestine in 1948. Ruth never talked to Ursula about this painful chapter of her life.

When Ms Horn received Ursula's query, she consulted the ITS central archive and found letters dating back to 1956 that pointed to Israel.

With help from Magen David Adom in Israel, Ms Horn learned that Nathan had died in 1986 - but also located his son, Eli, from another marriage.

Since the ITS provided contact information to the half-siblings, they have communicated via Skype. A personal meeting is likely later this year, according to the ITS.

"It's a very good, happy feeling - even pride - to know that we could help someone who was searching for years for their father, or for another relative," said Ms Horn, who has spoken to Ursula but not yet to Eli. "It was an extremely emotional conversation… [and] an affirmation of my work."

In 2015, ITS received some 15,500 queries about 20,000 individuals persecuted under the Nazi regime - over 25 per cent more than in 2014. In part, the increase reflects new regulations that expanded the categories under which survivors could claim pensions. According to the ITS, questions related to pensions are given top priority, considering the advanced ages of applicants.

But not all queries relate to reparations. Some, like Ursula's, relate to last-ditch efforts to find family.

"I advise everyone who has lost or is missing a family member since the National Socialist period not to miss this chance to find out what happened to them," Ms Horn said.

The ITS, a repository for Nazi-era documents seized by Allied troops, has an overarching aim of commemorating the victims of Nazi crimes. Its 30 million documents are accessible to survivors of Nazism and their families, as well as to historians and journalists.

Since 2013, the archive's original documents have been included in the Unesco "Memory of the World" registry. ITS is funded by Germany and is governed by representatives from 11 member states: Belgium, France, Germany, Greece, Israel, Italy, Luxemburg, Netherlands, Poland, United Kingdom, and the USA.