The Saudi-led Arab coalition waged a series of airstrikes on reinforcements of the Houthi rebels in Yemen's central province of Marib on Wednesday morning, a Yemeni government military source said.

"The strikes hit several pick-up vehicles carrying fighters from the western district of Sirwah to the frontlines of al-Mashjah and al-Kassarah," the source in Marib said on condition of anonymity.

He also said that the Yemeni government army repelled several ground attacks launched by the Houthi rebels at dawn in several frontlines in western Marib.

Meanwhile, Houthi-run al-Masirah TV reported seven coalition airstrikes on the Houthi positions in Sirwah.

The Iran-backed Houthis began in February a major offensive against the Saudi-backed Yemeni government army to capture the oil-rich province of Marib, which hosts nearly 2 million internally displaced people.

The United Nations has warned that the offensive on Marib could lead to a major humanitarian catastrophe.

A recent UN-brokered negotiation between Yemen's warring sides and other relevant parties has failed to produce a cease-fire agreement.

Yemen has been mired in a civil war since late 2014 when the Houthi militia seized control of several northern provinces and forced the internationally recognized government of President Abd-Rabbu Mansour Hadi out of the capital Sanaa.

The Saudi-led Arab coalition intervened in the Yemeni conflict in March 2015 to support Hadi's government.