ADEN, Yemen, April 17 (Xinhua) -- At least four people were killed and five others injured in a landmine blast in Yemen's southeastern province of Shabwa on Tuesday, police and medical sources told Xinhua.

According to a police officer based in Shabwa, the landmine which was planted by the Shiite Houthi militants in Osylan went off in the area, killing four people and injuring five others.

"I can confirm four people died and five others were injured. The Houthis who occupied Osylan previously planted hundreds of landmines. A civilian vehicle ran over one of that landmines today," the police source said anonymously.

Witnesses said a government vehicle rushed to the site and the injured people were transferred to a nearby hospital for treatment.

"The blast happens seconds after a car passed in the area that is not cleared yet of landmines," Ali Fahid, a resident, said.

Medical sources confirmed to Xinhua saying that landmines remained after the liberation of Osylan area and cause daily casualties from civilians.

Local humanitarian organizations estimate that thousands of civilians have been injured or killed by the explosives and landmines laid by Houthis in the ongoing conflict.

Some of the mines planted in mountainous areas and disguised as rocks and concealed in sandy dunes to target and stop the progress of the government forces backed by the Saudi Arabia-led coalition.

The impoverished Arab country has been locked into a civil war since the Shiite Houthi rebels overran much of the country militarily and seized all northern provinces, including capital Sanaa, in 2014.

Saudi Arabia leads an Arab military coalition that intervened in Yemen in 2015 to support the government of President Abd-Rabbu Mansour Hadi after Iran-backed Houthi rebels forced him into exile.

The United Nations has listed Yemen as the world's number one humanitarian crisis, with seven million Yemenis on the brink of famine and cholera causing more than 2,000 deaths.