UPDATE 1-Turkmen may sue Russia for "vacuum-bomb" pipe blast

* Talks continue on compensation for blast -Turkmen official

* Says Russia caused "vacuum-bomb effect" to blow pipeline

* May turn to international arbitration courts if talks fail

* Turkmen losing $1 bln/month, Russia gaining $800 mln/month

* U.S. official pushes for gas links bypassing Russia

(Recasts with comments from visiting U.S. official, analyst)

By Simon Shuster and Marat Gurt

MOSCOW/ASHGABAT, May 29 (Reuters) - Turkmenistan threatened to take Russia to court over last month's gas pipeline explosion, RIA news agency reported, escalating a dispute that has severed a vital energy link through Russia to Europe.

Turkmenistan blames Russia for blowing up the pipeline, which carries more than half of its most valuable export, by cutting the gas flows without enough warning.