Sana’a: Yemeni security officials say two tribesmen have been killed in intense government shelling east of the capital against locals suspected of attacks on a main oil pipeline and power lines.

The army’s major offensive in Marib province on Sunday was aimed at intimidating militants who attacked a crude oil pipeline just half an hour after repairs to it were completed a day earlier, the official said.

An Electricity Ministry official says an attack on a power station was behind electricity outages in the capital Sana’a and other cities on Sunday.

Some security officials suspect tribesmen allied with former longtime president, Ali Abdullah Saleh, of being behind the attacks in an attempt to undermine the new government.

The officials said some 30 tanks and other armoured vehicles were participating in the offensive against tribal fighters in the Wadi Obaida area of the central oil-producing province of Marib.

“The army is shelling areas containing armed men who blew up the oil pipeline and power lines in Maarib, “ a security source said, adding that some houses had been destroyed.

The fighters are said to be using infrastructure sabotage to press the government for handouts and the release of jailed tribesmen.

Yemen has been struggling to restore normality after President Abd Rabbo Mansour Hadi was elected in February following a year of protests that forced his predecessor Ali Abdullah Saleh to step down after 33 years in power.

Restoring stability is a priority for the US and its Gulf allies because of Yemen’s strategic position next to top oil exporter Saudi Arabia and major shipping lanes, and because it is home to a major wing of Al Qaida.

But armed groups have repeatedly sabotaged government installations, especially oil and gas pipelines and power facilities.

The last attack came on Saturday, half an hour after engineers completed repairs to one of at least three ruptures in the pipeline which transports crude oil from Marib to the Ras Isa export facility on the Red Sea.

On Sunday, gunmen opened fire on a power station in the Damashqa area of Marib, putting the facility out of action.

Fighters have also repeatedly targeted Yemen’s gas pipeline, which feeds the country’s only liquefied natural gas (LNG) terminal, a main source of state revenue, forcing the government to deploy troops to protect it.

The demands of the tribesmen are said to include government handouts or the release of relatives jailed for common crimes, attacking security forces or associating with Al Qaida.

“Those who carry out these attacks are individuals, but they seek refuge and protection from their tribes,” a Yemeni cabinet minister told Reuters.

“They are often demanding financial compensation or the release of relatives jailed for criminal offences.”

Yemeni officials say that under Saleh, the Yemeni government paid tribesmen monthly protection money to refrain from attacking power lines and the oil pipeline.

Hadi made some payments after he came to power but then stopped.

Yemen has been struggling to finance its daily needs. Donors have pledged a total of $8 billion to help the poorest Arab country overcome financial challenges. But little has trickled into Yemen so far.

Some 40 percent of the population lives below the poverty line of $2 per day. Yemen relies on revenues from e nergy sales for 60 percent of its income.