More than 50 Muslim states have blocked 11 gay and transgender organisations from attending a meeting at the United Nations next month dedicated to ending AIDS.

Some 51 states, including Egypt, Saudi Arabia, Iran, Indonesia, Sudan and Uganda, have objected to the groups attending the meeting.

Egypt wrote to the president of the 193-member GeneralAssembly on behalf of the Organization of Islamic Cooperation toobject to the participation of the groups.

It did not give areason in the letter - sparking a protest by the United States, Canada and the European Union.

Samantha Power (left), U.S. ambassador to the United Nations, has written to the General Assembly President, while Secretary-General Ban Ki-moon (right) has advocated for LGBT equality

Samantha Power, U.S. ambassador to the United Nations, wroteto General Assembly President Mogens Lykketoft and said thegroups appeared to have been blocked for involvement in lesbian,gay, bisexual and transgender advocacy.

'Given that transgender people are 49 times more likely tobe living with HIV than the general population, their exclusionfrom the high-level meeting will only impede global progress incombating the HIV/AIDS pandemic,' Power wrote.

U.N. officials said the European Union and Canada also wroteto Lykketoft to protest the objections by the Organization of Islamic Cooperation group, whosemembers include Saudi Arabia, Iran, Indonesia, Sudan and Uganda.

The issues of LGBT rights and participation in events at theUnited Nations have long been contentious.

Members and supporters of the LGBTI community march to commemorate the International Day Against Homophobia and Transphobia

U.N. Secretary-General Ban Ki-moon has advocated for LGBT equalitybut faced opposition from African, Arab and Muslim states aswell as Russia and China.

In 2014, Ban said the U.N. would recognise all same-sexmarriages of its staff, allowing them to receive its benefits.

Russia, with the support of 43 states including Saudi Arabia,China, Iran, India, Egypt, Pakistan, and Syria, unsuccessfullytried to overturn the move last year.

Ms Power added: 'We are deeply concerned that at every negotiation on a newGeneral Assembly gathering, the matter of NGO (non-governmentalorganization) participation is questioned and scrutinized.

'The movement to block the participation of NGOs on spuriousor hidden grounds is becoming epidemic and severely damages thecredibility of the U.N.'

Egypt wrote on behalf of the Organization of Islamic Cooperation to object to the participation of several gay and transgender groups - sparking a protest by the United States, Canada and the European Union

In February, the 54-member African Group, the Organizationof Islamic Cooperation and the 25-member Group of Friends of theFamily led by Belarus, Egypt and Qatar protested six new U.N.stamps promoting LGBT equality.

The Group of Friends of the Family promotes the traditionalfamily.