The Houthi fighters fired another ballistic missile against Saudi Arabia on Monday as battles between the pro-government and Houthi forces continued in several Yemeni provinces.
The new missile was launched from the district of Hamdan in northwest the capital Sanaa.
The Saudi-led coalition said it had intercepted the first one early Monday as the Houthi group threatened tough responses to continued war on Yemen.
The provinces of Marib, Jawf, Sanaa and Taiz have seen raging battles during which the pro-government forces made gains.
In the district of Nihm in Sanaa, Marib and Jawf the government forces retook new positions amid reports the forces are preparing for invading the capital.
In Taiz, battles resumed as the Houthi militants fired rockets on populated areas killing around 6 civilians, locals said, adding others were injured.
The battles coincided with fresh airstrikes by the Arab coalition in several provinces including Sanaa and Taiz.
The military operations violated a fragile ceasefire which was extended for one week on Sunday.
Separately, Human Rights Watch said the coalition carried out at least six apparently unlawful airstrikes in the capital Sanaa in September and October 2015, killing 60 civilians.
In a statement on Monday, HRW criticized Saudi Arabia and its key ally in the war in Yemen, the US, for failing to investigate indiscriminate attacks by the coalition in Yemen.
Human Rights Watch found no evidence of any military target in an airstrike on the Old City of Sanaa and on al-Asbahi neighborhood in September, it said.
“How many civilians will die in unlawful airstrikes in Yemen before the coalition and its US ally investigate what went wrong and who is responsible,” said Joe Stork, deputy Middle East director at Human Rights Watch. “Their disregard for the safety of civilians is appalling.