JERUSALEM, Israel -- In a signing ceremony Wednesday at the Israeli ambassador's home in Berlin, Defense Minister Ehud Barak and his German counterpart, Thomas de Maiziere, finalized a deal to acquire a sixth Dolphin-class submarine.   

Negotiations between the two countries have been in the works since 2005.

With Iran moving steadily toward acquiring nuclear arms capabilities, it's a welcome addition to Israel's naval fleet. 

Barak said the deal evidenced the "depth of Israel and Germany's relationship" and the importance of Israel's security to the German government.  He noted it will "substantially increase the capabilities and strength of…Israel in the face of ever-increasing challenges."

Israel already has three Dolphin-class submarines in its fleet.

The latest nuclear-capable submarine in the navy's fleet will also enhance Israel's defensive capabilities against a missile attack from Hezbollah, Iran's Lebanese-based proxy, estimated to have as many as 50,000 missiles in its warehouses.

In the 2006 Second Lebanon War, Hezbollah pounded northern Israel with nearly 4,000 rockets, many of them Grad-style Katyusha rockets.

Israeli defense officials believe Syria has supplied Hezbollah with medium- and long-range surface-to-surface missiles, including the Syrian-made M600, fashioned after Iran's Fateh-110.

That missile can deliver a half-ton payload up to 185 miles away, putting major Israeli cities such as Tel Aviv and Beersheva in the south well within its range.

Syria has one of the largest stores of chemical and biological weapons in the Middle East, including Mustard Gas and Sarin, and its own sizable cache of medium- and long-range missiles.

Last month, The Jerusalem Post quoted Secretary of State Christian Schmidt saying Germany wanted to "increase its defense cooperation with Israel," with an emphasis on "learning from the IDF about training and military doctrine."