TOP WRAP 7-Talk of compromise on both sides lifts hope for Russia-Ukraine breakthrough

(Adds Zelenskiy speech to U.S. Congress)

* "Close to an agreement" says Lavrov

* Russia describes status for Ukraine similar to Austria, Sweden

* Zelenskiy calls for help in speech to U.S. Congress

* Kyiv seeks ceasefire, withdrawal, security guarantees

By James Mackenzie and Natalia Zinets

KYIV/LVIV, Ukraine, March 16 (Reuters) - New talk of compromise from both Moscow and Kyiv on a status for Ukraine outside of NATO lifted hope on Wednesday for a potential breakthrough after three weeks of war.

Ukraine's President Volodymyr Zelenskiy said negotiations were becoming "more realistic", while Russian Foreign Minister Sergei Lavrov said proposals now being discussed were "in my view close to an agreement".

The Kremlin said the sides were discussing status for Ukraine similar to that of Austria or Sweden, both members of the European Union that are outside the NATO military alliance. Ukraine's chief negotiator said Kyiv was still demanding a ceasefire, the withdrawal of Russian troops, and binding international security guarantees to protect Ukraine in future.

Though the war still ground on with Ukrainian civilians trapped in cities under Russian bombardment, the signs of compromise sent relief through global financial markets. Shares in Germany - Russia's biggest energy market - were up 3.4%.

In a speech to the U.S. Congress that drew a long standing ovation, an unshaven Zelenskiy in an army green T-shirt appealed for tougher sanctions on Russia and more weapons to help his country fight "for the values of Europe and the world".

Speaking via a video link mainly in Ukrainian but closing in English, he invoked the Pearl Harbour and quoted Martin Luther King's "I have a dream" speech to call for a no-fly zone over Ukraine, although he acknowledged that Washington has ruled this out.

"In the darkest time for our country, for the whole of Europe, I call on you to do more," he said. Lawmakers were rapt as he played a video of clips showing dead and wounded children and buildings blasted by bombs.

Three weeks into the invasion, Russian troops have been halted at the gates of Kyiv, having taken heavy losses and failed to seize any of Ukraine's biggest cities in a war Western officials say Moscow expected to win within days.

Talks were due on Wednesday by a video link for a third straight day, the first time they have lasted more than a single day.

"The meetings continue, and, I am informed, the positions during the negotiations already sound more realistic," Zelenskiy said in a video address overnight.