UNITED NATIONS (Reuters) - The Palestinian Authority on Tuesday formally asked for renewed consideration by the United Nations Security Council of its 2011 application to become a full member of the world body.

Palestinian U.N. envoy Riyad Mansour told Reuters on Monday that the aim was for the council to take a decision at an April 18 ministerial meeting on the Middle East, but that a vote had yet to be scheduled.

Here are details on U.N. membership:

WHAT IS THE CURRENT STATUS OF THE PALESTINIANS AT THE U.N.?

The Palestinians are a non-member observer state at the United Nations, the same status as the Holy See.

The 193-nation U.N. General Assembly approved the de facto recognition of the sovereign state of Palestine in November 2012 by upgrading its observer status at the world body to "non-member state" from "entity." There were 138 votes in favor, nine against and 41 abstentions.

HOW DOES THE UNITED NATIONS ADMIT NEW MEMBER STATES?

Countries seeking to join the U.N. usually present an application to the U.N. secretary-general, who sends it to the 15-member Security Council for an assessment and vote.

Mansour sent a letter to U.N. Secretary-General Antonio Guterres on Tuesday requesting renewed consideration by the Security Council of a Palestinian application for full membership made in 2011. Guterres has sent the letter to the Security Council, U.N. spokesperson Stephane Dujarric said.

A council committee of the 15 members first assesses an application to see if it satisfies the requirements for U.N. membership. The application can then either be shelved or put forward for a formal vote in the Security Council. Approval requires at least nine votes in favor and no vetoes by the U.S., Russia, China, France or Britain.

If the council approves the membership request, it then moves to the General Assembly for approval. A membership request needs a two-thirds majority to be approved by the assembly. A country cannot join the United Nations unless both the Security Council and General Assembly approve.

WHAT HAPPENED TO THE PALESTINIAN APPLICATION IN 2011?

A U.N. Security Council committee assessed the Palestinian application for several weeks to see if it satisfied requirements for U.N. membership. But the committee was unable to reach a unanimous position and the Security Council never formally voted on a resolution on Palestinian membership.

Diplomats said the Palestinians lacked the minimum nine votes needed to adopt a resolution. Even if they had won enough support, the United States had said it would veto the move.