Riyadh (AFP) - Saudi Arabia is determined to prevent external "interference" in neighbouring war-torn Yemen, King Salman said in an annual address on Wednesday.

He did not explicitly refer to the kingdom's regional rival Iran but Saudi officials have accused Tehran and the Lebanese Shiite militant group Hezbollah of aiding rebels in Yemen.

Since March 2015, Saudi Arabia has itself led an Arab coalition conducting air strikes against the Shiite Huthi rebels and providing other assistance to local forces in support of President Abedrabbo Mansour Hadi.

"We will not accept any interference in the internal affairs of Yemen," King Salman said in an address opening a new session of the Shura Council, an appointed body which advises cabinet.

Salman said his country will neither accept that Yemen "becomes a base or a point of passage for whatever state or party to menace the security or the stability of the kingdom and of the region".

The Saudi-led coalition intervened after Huthi rebels allied with elite members of security forces loyal to Yemen's former president Ali Abdullah Saleh seized the capital Sanaa and overran other parts of the country.

The rebels have killed at least 110 civilians and soldiers in rocket fire and skirmishes along the Saudi frontier. They have also fired longer-range ballistic missiles over the border at Saudi Arabia.

International investigators last month said they had found a suspected "weapons pipeline" from Iran through Somalia to Yemen.

British-based Conflict Armament Research, which is primarily funded by the European Union, analysed photographs of weapons including assault rifles and rocket launchers to draw its conclusions.

Tehran has repeatedly denied sending arms to Yemeni rebels.

The Arab coalition, for its part, has faced repeated allegations of killing civilians, and on Tuesday the United States blocked the transfer of precision-guided bombs to Saudi Arabia.

-- 'Sometimes painful' measures --

A senior US administration official said the move reflected "strong concerns with the flaws in the coalition's targeting practices" and its overall conduct of the Yemen air war.

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Salman's son, Deputy Crown Prince Mohammed bin Salman, 31, has had overall responsibility for the Yemen campaign as he holds the post of defence minister.

King Salman underlined that Riyadh was open to a "political solution" in Yemen, whose security "is intrinsically linked to that of the kingdom".

The Yemen war has killed more than 7,000 people, about half of them civilians.

Its intervention has cost Saudi Arabia billions of dollars despite austerity at home to cope with fallen oil revenues.

On top of hikes in the prices of petrol, electricity and water over the past year, the cabinet in September imposed a wage freeze on civil servants, who make up the bulk of the workforce.

The government was left owing billions of dollars to private firms, chiefly in the construction sector, where tens of thousands of foreign workers were left unpaid.

King Salman said the government "took measures that were sometimes painful" because of the effect of lower oil prices, but that it has coordinated with other producers to stabilise the petroleum market.

"The kingdom experienced similar circumstances in the past three decades, obliging it to reduce its expenses, but it always succeeded in surmounting them," he said.