Pakistan's "nuclear umbrella" will cover Saudi Arabia, a source close to the kingdom's government said on Sunday, days after the two allies signed a surprise mutual defense treaty.

The source said that the deal had been in the works for years and that Saudi Arabia expected Pakistan's arch-rival India to understand the kingdom's security needs.

When asked if the deal meant Pakistan's nuclear weapons could be used to defend Saudi Arabia, Ali Shihabi, an analyst close to the royal court, said: "Yes, it does."