Military trucks - some pulling heavy artillery - are on the move in Crimea.

Witnesses reported seeing about 100 armored personnel trucks driving through Kerch, a primary entry to the Crimean peninsula from Russia.

Meanwhile, U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov are meeting in London.

They're trying to defuse tension ahead of a referendum that will decide whether the Russian-majority Crimea will leave Ukraine and join Russia.

(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY, SAYING:

"Obviously we have a lot to talk about. I look forward to the opportunity to dig into the issues and possibilities that we may be able to find on how to move forward together to resolve some of the differences between us and I look forward to a good conversation."

(SOUNDBITE) (Russian) RUSSIAN FOREIGN MINISTER SERGEI LAVROV, SAYING:

"I would also like to say that I'm pleased that we have an opportunity to meet today. T