(Updates with 20 government soldiers killed in blast)
SANAA, Sept 5 (Reuters) - At least 20 Yemeni soldiers loyal to exiled President Abd-Rabbu Mansour Hadi's government were killed in a bomb blast east of the capital Sanaa on Monday, officials said.
Two officials said the bomb went off at the entrance of a Yemeni army camp in central Marib province, which is mainly under the control of Hadi's government.
Several other soldiers were wounded in the blast, the officials said, adding that the number of casualties could rise as some of those injured were in serious condition.
It was not immediately clear if the bomb blast was a result of a deliberate attack or if it was an accident.
Hadi's government, backed by a Saudi-led Arab coalition, has been waging an offensive against Iran-allied Houthi fighters and supporters of former President Ali Abdullah Saleh since March last year. The Houthis hold the capital.
On Sunday, residents reported that a drone believed to be operated by the United States attacked a house in the Wadi Obeida tribal area in Marib province, killing six suspected al Qaeda militants.
Washington has kept up a campaign of drone strikes against militants who have exploited the 18-month-old civil war.
The Yemen conflict has split the security forces and allowed Islamist militants to flourish.
The United States has for years launched drone strikes against al Qaeda's powerful Yemen branch, which planned several foiled bombing attempts on Western-bound airliners and claimed responsibility for the 2015 attack at the Charlie Hebdo magazine's offices in Paris.
Al Qaeda in the Arabian Peninsula (AQAP) has grabbed territory in the south and east of Yemen, but an offensive by government and Emirati forces beginning in April pushed them out of many towns they had seized back into rural and mountainous areas. (Reporting By Mohammed Ghobari; Writing by Noah Browning and Sami Aboudi,; Editing by Toby Chopra)
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