GENEVA (Reuters) - Hollywood star Angelina Jolie arrived in Iraq on Tuesday and appealed for more international support for millions of people uprooted by war and violence, the U.N refugee agency said.

Jolie, who has been to more than 20 countries since becoming a goodwill ambassador for the UNHCR agency six years ago, visited a makeshift camp housing 1,200 people in Iraq and also spent hours speaking to Iraqis now living in Damascus, it said.

"I have come to Syria and Iraq to help draw attention to this humanitarian crisis and to urge governments to increase their support for UNHCR and its partners," the actress said in a statement issued through the agency.

"It is absolutely essential that the ongoing debate about Iraq's future includes plans for addressing the enormous humanitarian consequences these people face," she said.

About 4.2 million people have fled their homes in Iraq, where violence remains widespread more than four years after U.S.-led forces invaded the country and removed dictator Saddam Hussein.

The UNHCR and the Iraqi Red Crescent estimate that more than 60,000 Iraqis are uprooted every month, many choosing to leave ethnically mixed areas as a result of sectarian tension that has been rising since the February 2006 bombing of a Shi'ite shrine in Samarra.

More than 2 million people are displaced in Iraq, and a further 1.4 million are believed to be in Syria, which has kept its borders open to fleeing Iraqis. Jordan estimates it is hosting between 500,000 and 750,000 Iraqis.

The UNHCR has sought $223 million in aid to help distribute emergency supplies to the most needy of those displaced inside Iraq. It has also asked donors for funds to get an additional 150,000 Iraqi children into schools in neighbouring countries where their families have sought refuge.