INCIRLIK AIR BASE, Feb 19 (Reuters) - U.S. Secretary of State Antony Blinken on Sunday announced further aid to Turkey and said Washington would provide longer term help to Ankara as it seeks to rebuild following this month's earthquake.

A 7.8 magnitude earthquake struck Turkey's southeast and neighbouring Syria on Feb. 6, killing more than 45,000 people and leaving a million-plus homeless, with the economic cost of the disaster expected to run into billions of dollars.

Blinken arrived at Incirlik Air Force Base on Sunday for an official visit and discussions on how Washington can further assist.

From Incirlik, he took a helicopter ride with Turkish Foreign Minister Mevlut Cavusoglu to observe from above the devastation caused by the earthquake in the southern Hatay province, one of the hardest hit.

Reporters on the tour saw the uneven toll from the massive quake, with some buildings standing but with collapsed roofs and shattered windows. Other residential buildings leaned heavily to one side after lower levels had collapsed, and blue and white tents housing survivors were set up among the rubble.

"It's really hard to put into words. You see buildings still standing and then buildings collapsed, roofs destroyed and right next to it, something that's still standing," Blinken told reporters at the base, which Washington has used as a de facto headquarters to conduct its relief effort.

Almost two weeks after the earthquake, search and rescue operations are coming to an end, but Blinken said the United States would continue to help what he said would be "a long-term effort."

"When you see the extent of the damage, the number of buildings, the number of apartments, the number of homes that have been destroyed, it is going to take a massive effort to rebuild but we are committed to supporting Turkey in that effort," he said.

"The most important thing right now is getting assistance to people ... Simply put, the United States is here."

Since the earthquake, the United States has sent a search and rescue team to Turkey, along with medical supplies, concrete-breaking machinery and additional funding of $85 million in humanitarian aid that also covers Syria.

Blinken also said that President Joe Biden intends to authorise $50 million in Emergency Refugee and Migration Assistance Funds (ERMA) in response to earthquake in Turkey and Syria.

With the additional $50 million delivered through the State Department and USAID, total U.S. humanitarian assistance to support the earthquake response in Turkey and Syria reached $185 million, the U.S. State Department said.