BEIRUT (AFP) - Germany's spy chief arrived in Beirut on a mission cloaked in secrecy, as the German foreign intelligence agency denied the visit was linked to efforts to negotiate a prisoner swap between Israel and Hezbollah.

Ernst Urlau, accompanied by a five-member delegation, flew into Beirut's international airport amid tight security and was met by German ambassador to Lebanon Marius Haas, the ANI news agency said.

A spokeswoman for the Federal Intelligence Service (BND) declined to discuss the purpose of Urlau's visit, but denied reports he was serving as a go-between.

"The subject (of his talks) is not the prisoner exchange," she told AFP.

German daily Sueddeutsche Zeitung reported Friday, citing a BND officer, that Urlau wanted to thank Beirut for its help in capturing suspects behind a failed attempt to bomb German passenger trains in July.

But the government has sent conflicting messages about Urlau's visit.

A state secretary at the foreign ministry, Gernot Erler, said late Thursday that Urlau was on his way to Lebanon following calls from Israel for help in securing the release of its two soldiers captured by Hezbollah in a deadly cross-border raid in July.

"It is known that Israel hopes and expects that we do what we can to help. And we are happy to oblige," he told rolling news channel N24.

Lebanese newspaper As-Safir cited a high-ranking Lebanese official as saying German officials would meet General Security Director Major General Wafic Jezzini to discuss their contacts with Israel over the prisoners.