Saudi-led air strikes against rebels in Yemen have destroyed much of their military capabilities, but almost six weeks into the campaign the situation on the ground remains unchanged, analysts said.

Last month, the kingdom declared the strikes against the Iran-backed rebels that began on March 26 a success and announced the end to daily air raids, saying operations had entered a second phase focused on political efforts, aid deliveries and "fighting terrorism".

However, the air war has continued at the same rate amid mounting criticism over a hike in civilian casualties.

"The Saudis seem to be caught in several contradictions -- opening up a war with the Huthis and forces loyal to former president (Ali Abdullah) Saleh without a coherent plan for its ground component," said Neil Partrick, a Gulf analyst at the Royal United Services Institute for Defence and Security Studies.

So far, the coalition had only managed to bomb "military and civilian facilities needed by a Yemeni state that Riyadh claims is still ruled by President (Abedrabbo Mansour) Hadi," Partrick told AFP.

Saudi Arabia has said the coalition operations aim to restore "legitimacy", in reference to the government of Hadi, who took refuge in the kingdom as the rebels advanced on his refuge in the southern city of Aden.

Meanwhile, international concern has increased over the conflict, which has seen at least 1,200 people killed and thousands wounded since late March.

The United Nations has repeatedly warned that already impoverished Yemen faces a major humanitarian crisis.

The Huthi Shiite rebels descended from their stronghold in the mountains of northern Yemen last year, seizing the capital Sanaa in September before expanding farther towards the south.

- 'Air support not enough' -

They have been backed by troops loyal to Saleh, who ruled Yemen with an iron fist for 33 years before resigning under popular pressure in 2012.

On the other side, the so-called popular resistance committees, who make up the majority of fighters on Hadi's side, lack the experience and organisation needed to confront an organised force such as the Huthis, according to a military analyst in Aden.

"Air support from the coalition is not enough amid a lack of organisation on ground," said the analyst who requested anonymity.

Fighting in Aden between rival forces has raged on for weeks with neither side making significant gains.

Aden International Airport, the presidential palace, as well as the strategic Al-Anad air base in nearby Lahj are all still the control of the rebels, despite frequent coalition air strikes against them.

The capital itself is under the total control of the Huthis and their allies with no resistance from any pro-Hadi forces reported there.

On Sunday, Yemeni sources said the coalition had sent a "limited" ground force of several dozen soldiers to assist pro-government fighters in Aden.

Observers in Yemen say the force could be to help organise the ranks of pro-Hadi fighters.

Yemeni analyst Majed al-Mithhadi describes the Huthis as "an ideological army that was established in an environment of war."

The rebels had previously waged six wars against the central government in Sanaa between 2004 and 2010, and were even hit by Saudi forces late in 2009 and early 2010.

Such a force, in its familiar mountainous redoubt near the Saudi border, "cannot be defeated without a major ground intervention," said Mithhadi. "An air war will not change the situation on ground, regardless how intensive."

Partrick agreed, saying that "you cannot change political realities from the air".

The Saudis "hope to bomb the Huthis and Saleh's forces back to the negotiating table on compliant terms. This does not seem to be a very skilled strategy and perhaps reflects inexperience among the key Saudi players," says Partrick.

Shiite-majority Iran and the Sunni-ruled Gulf monarchies have been at odds over UN efforts to resume peace negotiations for Yemen.

Saudi Arabia and its coalition partners say the talks must be held in Riyadh, while Iran demands a neutral venue that could also accommodate its allies.

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