In written testimony read in Greek by his interpreter, as he sat quietly beside her, Mr. Yaacoub described how he would be picked up in a van to meet with his handler, Ayman, and used code words to confirm his identity. “I never saw the face of Ayman because he was always wearing a mask,” Mr. Yaacoub said.

He said he was trained in the use of weapons and had acted as a courier for the group inside the European Union; with his Swedish passport, Mr. Yaacoub was an ideal candidate for such missions. He also acknowledged staking out the locations where Israelis appeared in large numbers — a parking lot behind a Limassol hospital and a hotel called the Golden Arches.

But Mr. Yaacoub was adamant that he was not participating in a plot to kill Israeli tourists. “Even if they asked me to participate in a terrorist action, I would refuse,” he said. “I could never do that. I’m only trained to defend Lebanon.”

Cyprus has traditionally had strong ties to Israel, but even more so to the Arab world. The island was widely considered a safe place to do business, even informally viewed as something of a cease-fire zone for the region’s conflicts, said Petros Zarounas, an expert in international relations in Nicosia, the Cypriot capital.

“They considered it neutral ground where everyone will have access to Cyprus soil, to feel safe, secure, quiet,” he said.

But recently the island nation has grown closer to Israel, deepening economic ties. Like Bulgaria, Cyprus is a popular tourist destination, with nearly 40,000 Israelis visiting in 2012.

Officials in Cyprus have tried to keep the case as low-key as possible, declining in most instances to comment or to release documents. “It’s a very serious and delicate case,” the justice minister, Loucas Louca, said shortly after Mr. Yaacoub was arrested. “I don’t want to make a statement because any publicity could harm the case.”