BEIRUT, May 20 (Reuters) - An explosion was heard in eastern Beirut late on Sunday, a Reuters witness said. "There was a loud explosion here in east Beirut ... I can see a plume of smoke rising and people are going towards the area to see what happened," Reuters correspondent Tom Perry said. The blast came as Lebanese troops battled Islamist militants based in a Palestinian refugee camp in the north of the country on Sunday and 48 people were killed in Lebanon's bloodiest internal fighting since the 1975-90 civil war.
