* Building Patriot interceptors in Ukraine could take 12

months to five years

* Ukrainian President Zelenskiy met Trump at White House on

Tuesday

* Ambassador leaving post to defend against corruption

allegations related to personal property

By Andrea Shalal

WASHINGTON, July 30 (Reuters) - Ukraine hopes a new push for

ceasefire talks with Russia could halt the five-year war before

a potentially brutal winter, but needs new anti-ballistic

missiles now to defend against strikes by Moscow, the country's

envoy to Washington said on Thursday.

Olha Stefanishyna told reporters that Ukraine was in

discussions with the Pentagon about a license to produce Patriot

PAC-3 missiles itself, but that process could take 12 months to

five years. Discussions were also underway about Ukraine

agreeing to a long-term purchase of PAC-3 missiles, and then

swapping positions in the production line with another buyer.

Officials from Patriot maker Raytheon Co had already been to

Ukraine, and Lockheed Martin Corp ( LMT ), which builds the

PAC-3 interceptors for the air defense system, was working to

send a team of experts to the country as well, Stefanishyna told

an event hosted by the Christian Science Monitor.

"The devastating effect of every overnight attack right now

is unbelievable," Stefanishyna said. "Last night and the night

before, it was 30 to 40 ballistic missiles."

While Ukraine was able to defend against Iranian- and

Russian-built drones, it had not yet developed an effective way

to defend against ballistic missiles, whose production is being

rapidly increased by Russian President Vladimir Putin.

"He has an intention to destroy Ukraine, and that's why, you

know, we're looking for different capabilities. We have been

successful in everything, but so far, for this winter, we need

the missiles."

Ukrainian President Volodymyr Zelenskiy met U.S. President

Donald Trump at the White House on Tuesday to push for new air

defenses against the escalating Russian attacks, and to

jumpstart a new diplomatic effort to end the war.

That could include a potential visit by U.S. negotiators

Steve Witkoff and Jared Kushner to Kyiv, Stefanishyna said. No

date had been set for Kushner and Witkoff's visit, but it could

happen as early as next week or later, she said.

Zelenskiy repeated his offer to halt the fighting at the

existing battle lines, and use that as a starting point for

discussions, Stefanishyna said, while stressing the need to take

action before the approaching winter.

Stefanishyna confirmed Ukrainian media reports that she had

offered to resign from her post just a year after taking over as

Ukraine's ambassador to the U.S., saying she would return to

Ukraine to defend herself against corruption allegations

involving some personal property declarations.

She said Zelenskiy had not asked for her resignation and did

not want her to leave her post, but she felt it best for her and

her family to "defend my case" in person.