Jordan's king has announced that security along the country's northern frontier has been tightened, but Syrian refugees fleeing violence will still be allowed to enter, officials said Monday.

King Abdullah II said at a Cabinet session late Sunday that government plans to protect the border were "moving in the right direction," a Royal Court statement said, without providing details.

"It is our duty to protect citizens, but at the same time, we have to open our doors to our Syrian brothers, and I'm very optimistic that the situation is moving in the right direction," the king said.

Government spokesman Sameeh Maaytah said the northern region was secured against "any infiltrations."

Jordan hosts more than 140,000 Syrian refugees. It has been concerned about Syria's civil war spilling across the border.

Jordan's first large-scale refugee camp for Syrians could be opened this week in the northern frontier region as numbers spike, U.N. refugee agency officials said.

"We expect the Zataari camp will open in the next couple of days," UNHCR representative to Jordan Andrew Harper said. He would not give a specific date.

Harper said the camp would initially host 5,000 refugees, but could eventually accommodate up to 130,000.

Since the uprising in Syria broke out in March 2011, most refugees fleeing to Jordan have been housed in apartments or with private families. Others have stayed in heavily-guarded housing compounds in several towns along the border. As the influx increased earlier this month, the government was forced to open a trailer park camp in the northern town of Ramtha to house Syrian families.

Zaatari will be the first tent camp in the country, like those found along Syria's border with Turkey. Maayteh said earlier that the camp had to be set up because Syrian refugees could no longer be absorbed into border communities.

Authorities here had been reluctant to set up tent camps, possibly to avoid angering Syrian President Bashar Assad's autocratic regime by showing images at his doorstep of civilians fleeing his military onslaught against them. Syria also has been one of Jordan's largest Arab trade partners, with bilateral trade estimated at $470 million last year.

A separate camp, which was to host the UNHCR tents, was set up months ago in the town of Ribaa Sarhan near the Syrian border, but has remained unused. Recently, authorities said it could be opened to serve as an `overflow' facility to process newly-arrived refugees.

Jordan continues to host hundreds of thousands of Palestinian and Iraqi refugees. It said the latest influx of Syrians is taxing its scarce health resources and water supplies and has appealed for international aid.

The U.S. Embassy in Jordan meanwhile announced on Sunday plans to give the kingdom an additional $100 million in aid, in part to help bear the refugee burden.

The money "will be in direct budget support and will help the Government of Jordan as it works to address the strains on the national budget as result of the continuing effects of the global financial crisis, the repeated disruption of the Egyptian natural gas pipeline, and the added cost of providing subsidized social services and basic commodities to those fleeing the violence in Syria," an embassy statement said.

The flow of gas from Egypt has been disrupted by militant attacks in the lawless Sinai Peninsula.