• Sources say US encouraged idea of a Syrian operation in east Lebanon
  • Syria sees risks, including possible Iranian attack
  • Hezbollah was enemy of Sharaa, rebels during Syrian war
  • Syrian official: Damascus and Arab allies agree on staying out
  • Lebanon receives assurances from Syria

DAMASCUS, March 17 (Reuters) - The United States has encouraged Syria to consider sending forces into eastern Lebanon to help disarm Hezbollah, but Damascus is reluctant to embark on such a mission for fear of being sucked into the war in the Middle East and inflaming sectarian tensions, five people briefed on the matter said.

The proposal to Syria's U.S.-allied government reflects intensifying moves to disarm Iran-backed Hezbollah, which opened fire at Israel in support of Tehran on March 2, prompting an Israeli offensive in Lebanon.

The idea was first discussed by U.S. and Syrian officials last year, said two of the sources - both Syrian officials - and two others familiar with the discussions. All spoke on condition of anonymity because of the sensitivity of the matter.

The idea was raised again by U.S. officials around the time the U.S. and Israel began their war against Iran. The two Syrian officials said a U.S. request came shortly before the war began. A Western intelligence source said it was just after it started.

Reuters spoke to 10 sources for this article - six Syrian officials and government advisors, two Western diplomats, a European official and a Western intelligence source. All said Syria's Sunni Islamist-led government had been cautiously considering a cross-border operation but remained hesitant.

U.S. encouragement for a Syrian operation in eastern Lebanon and Syria's hesitation to carry one out have not previously been reported.

A U.S. State Department spokesperson declined comment on "private diplomatic communications", and referred Reuters to the Syrian and Lebanese governments for comments on their operations.