A bipartisan group of US senators introduced legislation on Thursday seeking to punish Saudi Arabia over the killing of Saudi journalist Jamal Khashoggi and for the kingdom's role in the devastating war in Yemen.

The move comes hours after the US slapped economic sanctions on 17 Saudis allegedly involved in the murder of Khashoggi inside the kingdom's consulate in Istanbul.

If the bill were to become law, it would suspend weapon sales to Saudi Arabia and prohibit US refuelling of Saudi coalition aircraft conducting air raids in Yemen.

It also would impose sanctions on anyone blocking humanitarian access in Yemen and anyone supporting the Houthi rebels.

The Senate proposal comes a day after House Republicans moved to block a bill aimed at ending US support for the Saudi involvement in Yemen.

Sponsored by three Republican and three Democratic senators, the Senate legislation, reflects growing dissatisfaction in the upper house of Congress over the Yemen war, which has killed more than 10,000 people and created major humanitarian crisis.

That frustration was exacerbated by the killing of Khashoggi at the Saudi consulate last month.

Saudi Arabia initially rejected its officials were behind the killing, but as Turkish authorities continued to leak evidence of high-level involvement, Riyadh eventually admitted its agents had played a role in the killing with a series of contradictory explanations.

On Thursday, Saudi Arabia's top prosecutor said they will seek the death penalty for five individuals accused of carrying out Khashoggi's murder.

The authorities said 21 people were in custody over the killing, with 11 indicted and referred to trial.

Saud Al-Qahtani, a key aide of Crown Prince Mohammed bin Salman, has been banned from travelling and remained under investigation, Saudi officials said.

Ankara dismissed the latest account by the kingdom as "inadequate".

Turkish officials have said it is unlikely Khashoggi could have been killed without the knowledge of the crown prince, with President Recep Tayyip Erdogan saying the orders came from "the highest levels of the Saudi government".

'Insufficient'

Earlier on Thursday, US politicians welcomed the US sanctions against Saudi officials, but many also said the punitive measures did not go far enough. 

Republican Senator Bob Corker called the sanctions a "significant step", but added that he hopes additional action will be taken.

"I have a lot of concerns about the trajectory that Saudi Arabia is on right now, and I think a price needs to be paid," the chairman of the Senate Foreign Relations Committee, said in a statement.

Corker said he has requested a meeting with Defense Secretary James Mattis, Secretary of State Mike Pompeo and CIA Director Gina Haspel "to share with us [the Senate] exactly what is happening with the US response to Saudi Arabia".

Bob Menendez, the top Democrat on the Senator Foreign Relations Committee and one of the Senators who authored Thursday's bill, said the sanctions were a "good first step", but with the Saudi announcement about the death sentences, the US move "looks like a coordinated attempt to sweep this case under the rug."

Others took their calls a step further, demanding the US to take action against the Saudi crown prince himself.

Democratic Senator Tim Kaine, who represents Virginia, where Khashoggi lived, said the sanctions were "insufficient" and suggested the administration of US President Donald Trump is "following the Saudi playbook".

Others targeted included Maher Mutreb, another aide to the prince, who was pictured at Saudi consulate in Istanbul on the day of the slaying.

"The Saudi officials we are sanctioning were involved in the abhorrent killing of Jamal Khashoggi," Treasury Secretary Steven Mnuchin said.

"These individuals who targeted and brutally killed a journalist who resided and worked in the United States must face consequences for their actions," he added.

The sanctions block the individuals' assets in the US and generally prohibit US persons from engaging in transactions with those sanctioned.

The State Department called the sanctions "an important step in responding to Khashoggi's killing".

"This was state-sponsored murder. We need accountability," Kaine tweeted.

Democratic Senator Ben Cardin said he remains "concerned that the [Trump] administration is enabling the Kingdom of Saudi Arabia in its effort to protect Crown Prince Mohammed bin Salman from accountability".

He added, "It is difficult for any reasonable person with knowledge of Saudi Arabia's government to believe such high-level officials would conduct a plot of this significance without the direction of the Crown Prince."

Saudi officials maintain bin Salman had nothing to do with Khashoggi's death.

'Involved in abhorrent killing'

The US sanctions on the 17 Saudi nationals were issued under the Global Magnitsky Act, which was triggered last month by a bipartisan group of Senators. The measures on Thursday targeted al-Qahtani, who is believed to have managed the operation to kill the Saudi writer.

Agencies