UPDATE 2-Libyan PM visits scene of tribal clashes in desert
* Ceasefire holding in oasis town of Sabha-Reuters reporters
* Prime minister meets representatives of warring sides
* Clashes underline fragility of Libya after Gaddafi
* Second stand-off in west of country (Updates with more PM quotes in paragraphs 12-13)
By Marie-Louise Gumuchian
SABHA, Libya, April 1 (Reuters) - Libya's prime minister flew to a desert oasis city on Sunday to try to patch up a tribal dispute that has killed about 150 people over the past week and underscored the ethnic faultlines threatening Libya's stability.
A Reuters team that flew with the prime minister to Sabha, about 750 km south (450 miles) of the Libyan capital, said a ceasefire appeared to be holding between the Tibu ethnic group and the Sabha militias with which they had been clashing.
Smashed windows at a conference centre and burned-out vehicles in a Tibu-controlled neighbourhood bore testimony to the fighting over the past days, some of the worst since a revolt last year ousted Libyan leader Muammar Gaddafi.
Asked about the situation in Sabha, Prime Minister Abdurrahim El-Keib told Reuters: "It's much better than I thought." Continued...