More than 140 people were killed and over 525 wounded on Saturday, by a Saudi Arabian airstrike on a funeral. (See nytimes, rt, theguardian, and foxnews.)
The questions are:
As you can read on the Wikipedia article on the Royal Saudi Air Force and Saudi-Arabian ground forces, Saudi Arabia has the following aircraft capable of performing ground strikes:
They further have 86 F-15C's (United States) which are pure air-superiority fighters not equipped to attack ground targets and various unarmed aircraft supplied by UK, US, Pakistan, Switzerland, France, Sweden, Ukraine and Italy.
Their main suppliers for tanks and heavy artillery are the US and France, minor suppliers are UK, Brazil and China.
Russia has agreed to supply Saudi Arabia with air defence missiles.
Personal firearms are supplied by Belgium, Germany, Austria, Russia and the US.
The United Nations Security Council can enact sanctions against individual countries. A commonly used sanction against countries which are considered a security threat are trade embargoes which forbid all UN countries from exporting weapons to a country.
Such a decision by the security council can be vetoed by any of the UN veto powers. The United States, United Kingdom and France are among these veto powers, so they would consider their own economical interests before allowing such sanctions to pass. Also, Saudi-Arabia has a lot of control over the global oil market, which gives them quite a lot of leverage against the international community.
The USA
The United States sold more than $80 billion in military hardware between 1951 and 2006 to the Saudi military.
https://web.archive.org/web/20101111112056/https://fas.org/asmp/profiles/saudi_arabia.htm https://www.aljazeera.com/economy/2014/04/15/saudis-lead-middle-east-military-spending/
The UK
The United Kingdom has also been a major supplier of military equipment to Saudi Arabia since 1965. Since 1985, the UK has supplied military aircraft—notably the Tornado and Eurofighter Typhoon combat aircraft—and other equipment as part of the long-term Al-Yamamah arms deal estimated to have been worth £43 billion by 2006 and thought to be worth a further £40 billion.
Canada
Canada doubles weapons sales to Saudi Arabia despite moratorium: Newly released figures show Canada sold nearly C$3bn (US$2.2bn) worth of military equipment to Saudi Arabia in 2019 – more than double the total of the previous year, reported the Globe and Mail. The bulk of the exports were light armoured vehicles, part of a deal with the Saudis worth C$14.8bn.
Saudi Arabia also closely cooperates militarily with Pakistan
For some years there have been reports that the Saudis might have acquired nuclear weapons, in all likelihood bought from Pakistan due to the kind of money only a major oil-producing country could afford. In terms of numbers, billions of dollars have been mentioned, although much of that is speculation.
https://archive.org/details/allahsbombislami0000vent/page/150/mode/2up
France, Spain
France’s weapons sales to Saudi Arabia rose 50 pct in 2018 despite the government calling for an end to the “dirty war” in Yemen, figures released on Tuesday showed.
An annual government report showed that total arms sales rose 30 percent to 9.1 billion euros in 2018, driven by a sharp increase in sales to European allies.
The organizations expect the [Spanish] Government to account for “a record volume of sales” that between 2018 and 2019 amounted to 21,825 million euros, of which 7,880 million euros have already been exported”.
and Germany, until recently
German media outlet DW reported on Monday that the German government had approved an extension of the arms embargo on Saudi Arabia, which will now last until December 31, 2020. This decision marks the third extension to the arms embargo, which was initially enacted in late 2018 after the killing of Saudi dissident Jamal Khashoggi, who was assassinated by Saudi agents inside the Saudi consulate in Istanbul, Turkey, in October 2018.
https://www.politico.eu/article/germany-extends-saudi-arabia-arms-export-ban-into-2020/
https://www.cia.gov/library/publications/the-world-factbook/geos/sa.html
As some answers say, many people give weapons to Saudi Arabia. The United States has given arms to Saudi Arabia in a 2017 deal with the combined arms sold to Saudi Arabia worth $110 billion. This deal included tanks, combat ships, missile defense, and radar. For the Yemen conflict, the United States secretly provided refueling and logistics for Saudi Arabia. In 2017, Russia also sold $3.5 billion worth of weapons to the nation. International laws like sanctions could be made, but considering that the United States is a global superpower and some consider Russia to be becoming a potential global superpower, enforcing such laws would be a completely different issue...
