The abduction of a senior Jordanian diplomat in Lebanon has raised the threat of an underground war between Syrian and Jordanian agents, Arab diplomatic sources said. Jordan has openly accused Syrian military intelligence of kidnapping charge d'affaires Hisham Moheisen in Beirut last Friday. Amman vows revenge if he comes to harm. Syria has dismissed the charge as part of what it calls a Jordanian campaign of hatred orchestrated by Prime Minister Mudhar Badran. The diplomatic sources said the incident has brought a simmering political conflict between the two erstwhile allies almost to t he boiling point.