Nigeria is refusing to say how it will vote when the United Nations Security Council decides on the Palestinians' request for U.N. membership, as increasing diplomatic pressure mounts on the oil-rich West African nation.

Nigeria appears to be a crucial vote as Palestinians try to secure support from at least nine of the 15 council members. The U.S. has said it will veto the request. However, the U.S. could avoid that if Palestinians fail to get those nine votes.

On Thursday, Palestinian Foreign Minister Riad Malki told reporters that both Nigeria and Gabon assured him of their support. But Damian Agwu, a spokesman for Nigeria's Foreign Ministry, said Sunday that Nigeria had yet to offer their support to anyone on the matter.

"We have noted the positions of both parties. Both have been lobbying Nigeria both inside the country and outside," Agwu told The Associated Press. "We are keeping how we are voting on that close to our chest."

Agwu said Nigeria supported a "two-state solution" for Israel and the Palestinians, but said it would be "diplomatically tactless" for the country to say now how it will vote.

The Palestinian group has asked the U.N. to grant full membership to a state in the West Bank, Gaza and east Jerusalem, lands Israel captured in the 1967 Mideast war. Nigeria, a non-permanent member of the Security Council serving a yearlong term on the body, is viewed as a swing vote.

The diplomatic push on Nigeria has already begun, with Palestinian officials saying they planned to send a delegation to the country to argue their case. But oil-rich Nigeria already falls under the strong influence of the U.S., which is one of the country's top buyers of crude oil pumped from its southern delta. The United Kingdom also carries heavy political power in its former colony as well.