Yemen officer killed in shootout with northern rebels

(Adds state news agency statement)

SANAA, March 8 (Reuters) - A Yemeni army officer and six of his bodyguards were killed in a shootout with Shi'ite Muslim rebels on Thursday in the north of the country, where insurgents have snatched territory during a year of anti-government protests, an official said.

Political upheaval that paralysed Yemen for most of 2011 has severely weakened central government control over swathes of the country, allowing the rebels - known as Houthis - effectively to carve out a state within a state along the border with top oil exporter Saudi Arabia.

"The head of an army brigade and six of his bodyguards were killed in an exchange of gunfire with the Houthis when they refused to stop at an armed checkpoint set up by the Houthis in the Harf Safyan district of Amran province, north of Sanaa," the official said, adding that three Houthis had also been killed.

State news agency Saba later named the officer as Nashwan Ali al-Klibi, and said he and four of his companions had been killed when they were attacked on their way to the capital Sanaa from the north of the country.

The head of the Houthis said two of their fighters had died and a third was missing. He blamed the army officer for provoking the violence.

"This brutal, unjustified aggression reveals the barbarity of this officer and those who stand behind him and their disregard for the blood of the people and their hatred for the sons of the northern provinces," Abdulmalik al-Houthi said in a statement.

Amran province, where the gun battle took place, is partly controlled by Houthis.

Saudi Arabia briefly fought the Houthis in north Yemen after they grabbed Saudi territory in 2009.

The U.S. envoy to Yemen said last month there were signs that Shi'ite Iran was becoming more active in Yemen, posing a threat to the country's security and stability. Iran denies interfering there.

Predominantly Sunni Saudi Arabia, a close U.S. ally, says Iran is fomenting unrest among Shi'ites in its east and in neighbouring Bahrain.

The Houthis have accused Riyadh of smuggling weapons to fellow Sunnis in northern Yemen, with whom they have fought regularly in recent months.

Rebellion in the north is just one of a host of challenges facing President Abd-Rabbu Mansour Hadi, who officially replaced Ali Abdullah Saleh last month.

Apart from a looming humanitarian crisis, the south of the country is home to rising secessionist sentiment and a tenacious arm of al Qaeda, which has launched a string of deadly attacks on the army since Hadi took office. (Reporting by Mohammed Ghobari; Writing by Isabel Coles; Editing by Tim Pearce)