MUNICH – The United States is prepared to hold direct talks with Iran in the standoff over its nuclear ambitions, Vice President Biden said Saturday – but he insisted that Tehran must show it is serious and Washington won’t engage in such talks merely “for the exercise.”

During a trip to an international security conference in Germany, Biden also addressed Syria’s civil war. He met with top Syrian opposition leader Moaz al-Khatib and with Foreign Minister Sergey Lavrov of Russia, a longtime ally of Syrian President Bashar Assad. Separately, al-Khatib met with Lavrov for the first time, offering a glimmer of hope for stalled diplomatic efforts to resolve the conflict, though the Russian minister later sounded skeptical.

Washington has indicated in the past that it’s prepared to talk directly with Iran, and talks involving all five permanent members of the U.N. Security Council plus Germany have made little headway while several rounds of international sanctions have cut into Iran’s oil sales and financial transactions.

Biden told an international security conference that “there is still time, there is still space for diplomacy backed by pressure to succeed.” Asked when Washington might hold direct talks with Tehran, Biden replied: “When the Iranian leadership, the supreme leader (Ayatollah Ali Khamenei), is serious.”

Missing American in Turkey dead

A New York City woman who went missing while vacationing alone in Istanbul was found dead on Saturday, and police detained nine people for questioning in connection with the case, Turkey’s state-run news agency said.

Sarai Sierra, a 33-year-old mother of two, was last heard from on Jan. 21, the day she was to fly home. Her disappearance attracted a lot of interest in Turkey, where the disappearance of tourists is rare, and Istanbul police had set up a special unit to find her.

The state-run Anadolu Agency said the body of a woman was discovered Saturday evening near the remnants of ancient city walls and that police later identified it as Sierra’s.

Nebraska official resigns over calls

Nebraska Lt. Gov. Rick Sheehy resigned abruptly Saturday in a scandal involving thousands of calls to four women on his state-issued cellphone, including one woman who said she had a romantic relationship with the politician.

Gov. Dave Heineman announced Sheehy’s resignation in a hastily called news conference Saturday morning. Sheehy, a Republican, had been considered the front-runner in the 2014 gubernatorial race and had been endorsed by Heineman.

“As public officials, we are rightly held to a higher standard,” Heineman said. “I had trusted him, and that trust was broken.”

Syrian rebels take key supply route

Syrian rebels captured a strategic neighborhood near Aleppo’s international airport on Saturday, putting opposition fighters in control of a key road that the regime has used to ferry supplies and reinforcements to soldiers fighting in the embattled northern city, activists said.

Elsewhere in the nation, fighting continued unabated, killing more than 60 people nationwide, according to activists.