Foreign Minister Margot Wallstrom said the text has "no clear definition of nuclear weapons and there are a number of issues that must be answered." Wallstrom told a news conference that there is no majority in Sweden's parliament, the Riksdagen, to sign the convention. The country's two-party, center-left minority needs the backing of a majority to sign it.
The Social-Democratic-led government of Sweden, which is not a NATO member, has been internally divided over the issue, with some saying it could find its cooperative relationship with the alliance weakened if it endorses the U.N. convention. NATO supports the idea of a world without nuclear weapons, but doesn't believe it can be achieved by imposing a ban through the United Nations convention.
She added the government will continue "its nuclear disarmament efforts" and will continue "to work for a ban on nuclear weapons" as an observer. Wallstrom said "the goal of the government's work is clear: Sweden is a strong voice in the world for a nuclear-free world."
In a statement, the Swedish Foreign Ministry said a conference in 2020 to review the UN Treaty on the Prohibition of Nuclear Weapons "needs to lead to concrete disarmament pledges from nuclear-weapon states. If this does not happen, the security policy situation will be worsened."
It said Sweden considers nuclear disarmament "a key priority" and that "the threat posed by nuclear weapons is greater now than for several decades. A number of states are modernizing their arsenals, and the lack of trust between states is an urgent problem."
There are believed to be about 15,000 nuclear weapons in the world today. Amid rising tensions over Iran and North Korea's nuclear and missile tests, the United Nations says the threat of a nuclear attack is at its highest level since the end of the Cold War.
Under the UN treaty's terms, non-nuclear nations agreed not to pursue nukes in exchange for a commitment by the five original nuclear powers — the U.S., Russia, Britain, France and China — to move toward nuclear disarmament and to guarantee other states' access to peaceful nuclear technology for producing energy.