Dubai: Rocket fire from Yemen struck a power station in southern Saudi Arabia Friday, emergency workers said, a day after US Secretary of State John Kerry announced a new peace initiative.

The move appeared to be a tacit rejection of a US-backed peace initiative in Yemen which calls for a unity government, which Al Houthis have been pushing for.

Observers say the move shows Al Houthis obstinate refusal to find a solution to the conflict despite concessions made by the internationally-recognised Yemeni government which is staunchly backed by Riyadh.

The Al Houthi militant group put out a statement promising to redouble its efforts on the battlefield. The new peace push also calls on Al Houthis to pull out of the capital and hand over their heavy weapons to a third party.

These include the ballistic missile weapons described by Kerry as a threat to Saudi Arabia and the region.

During a meeting in Jeddah with US, UK and Gulf officials, Kerry said Washington was “deeply troubled” by rebel attacks on Saudi territory, where more than 100 soldiers and civilians have been killed in cross-border bombardments and skirmishes.

Kerry alleged that Iran, Saudi Arabia’s regional rival, had shipped missiles to Yemen.

The Al Houthi strike on the transformer in Najran, which lies just across the Yemen border, marked a rare hit on Saudi infrastructure despite months of periodic bombardment of the area.

Attacks have intensified since the suspension in early August of United Nations-brokered peace talks between the Iran-backed Al Houthi rebels and their allies, and Yemen’s internationally-recognised government.

The civil defence agency in Najran said it had responded to a rocket strike from Yemen on an electrical station, which caused no injuries, and that the blaze was extinguished.

A purported video of the incident circulating on social media showed heavy black smoke rising behind white storage tanks licked by orange flames.

Nine people have been killed in Najran since August 16, when seven lost their lives in a single strike.

A Saudi-led military coalition has also intensified its air raids in Yemen since the peace talks collapsed.

The coalition intervened in March last year to support President Abd Rabbo Mansour Hadi after Al Houthis and their allies seized much of Yemen.

Rebels continue to hold the capital Sana’a.