At least three government soldiers were wounded in overnight clashes with Houthi rebels in Yemen's southwestern city of Taiz, a local military source said on Monday.

The fighting flared in the military base of al-Tashrifat in the eastern part of Taiz, the source said on condition of anonymity. Residents reported hearing artillery and heavy machine gun fire throughout the night.

The Houthis have not commented on the fighting.

The government controls much of Taiz, but the Houthis have advanced to the north and east of the city. Clashes in and around Taiz have been on and off since the two sides agreed to a truce in April last year.

The United Nations is trying to open the main roads linking the city of Taiz with other provinces, which have been closed due to the fighting. Opening the roads and lifting the blockade could pave the way for a comprehensive political settlement to the Yemeni crisis.

Previous initiatives to open the roads and lift the siege have failed.

Yemen has been mired in a civil war since late 2014 when the Houthis seized control of several northern provinces. The war has killed tens of thousands of people and pushed the country to the brink of starvation.