A Yemeni journalist says Saudi Arabia is using US-manufactured cluster bombs in its deadly airstrikes targeting civilians in the impoverished country.

Speaking on a live TV program on Friday, Hasan al-Buhaiiti displayed the fragments of a US-made bomb that had been dropped by a Saudi jet on the Hamdan district of Yemen's west-central Sana'a province on Thursday.

At least six people, including two children, had been killed in the Saudi air raid.

Buhaiiti said local children had found the yellow-colored bombs at the site of the Saudi strike.

He also condemned US complicity in the Saudi-led war on Yemen, saying Washington provides fuel for Saudi warplanes and supplies logistics and weapons to the Riyadh regime.

"And I want to ask the US ambassador to the United Nations, who is supplying these bombs to the Saudi coalition? We don’t have these bombs in Yemen," he said.

"The only country that is actually using these bombs on Yemen, and the only country that has a blockade on Yemen, the only fighter jets that are in the sky of Yemen, they are Saudi fighter jets that are fueled by US jets. All the coordinates, all of the satellite images, all the logistics supplies are coming from the United States," he added.

The Yemeni journalist further noted that the US is just caring about the type of the Yemeni missiles, which are used "only to defend Yemen."

"The Americans only care about money, about how much they want to get from the Saudi-led coalition, how much oil they can get. And they exchange the Saudi oil just for money, to give these bombs to the Saudis so that they could drop them on civilians. So, I would like to see the United States will explain how come these bombs are in Yemeni villages," Buhaiiti pointed out.

Separately on Friday, the UN warned that April had been the deadliest month this year so far amid a "sharp" increase in Yemeni civilian casualties.

Saudi Arabia and its allies launched a war on Yemen in March 2015 in support of Yemen’s former Riyadh-friendly government and against the Houthi Ansarullah movement

The military campaign has killed and injured over 600,000 civilians, according to the Yemeni Ministry of Human Rights.

Saudi Arabia has also imposed a blockade on Yemen, which has halted humanitarian deliveries of food and medicine to the conflict-ridden state.

Several Western countries, the US and the UK in particular, are accused of being complicit in the aggression as they supply the Riyadh regime with advanced weapons and military equipment.

Yemeni forces regularly target positions inside Saudi Arabia in retaliatory attacks against the Riyadh-led military operation.