* 20,000 flee in a week as violence in southern Syria escalates
* Over 300,000 Syrians now in Jordan (Adds details)
By Suleiman Al-Khalidi
AMMAN, Jan 23 (Reuters) - Around 20,000 Syrian refugees have fled to neighbouring Jordan in the last seven days due to escalating violence in southern Syria, the fastest influx since the start of the uprising against President Bashar al-Assad two years ago, Jordan's foreign minister said on Wednesday.
"What we have seen in terms of influx of Syrian refugees coming to Jordan is ... unprecedented, larger than any other time in the last two years," Nasser Judeh told Reuters. "We have had 20,000 Syrians coming into Jordan since last Thursday."
He said 6,200 refugees had crossed within the past 24 hours.
"We now stand at over 300,000 Syrians on Jordanian territory since March 2011."
Judeh attributed the spike in numbers to the level of military activity in the south - several towns and villages in the southern region of Syria are being bombarded.
"There is heavy exchange of fire which we are monitoring and this of course is reflected in the numbers coming to Jordan," the minister said.
Officials say until the latest surge in numbers, Jordan had allowed in an average of 6,000 refugees every week in the last six months.
Although the flow of refugees is causing concern in Jordan, the kingdom will continue to keep its borders open but wants other countries to help boost its ability to cope.
"We are making contacts with major donor countries to tell them the camps in Jordan are almost reaching full capacity so we need help to continue building infrastructure for further camps," Judeh said.
Jordan's main Zaatari camp along the border hosts at least 60,000 Syrian refugees, with the rest spread across the country.
Jordan, Lebanon and Turkey each host more than 130,000 registered refugees, and relief workers predict the numbers will increase as violence escalates.
"The political decision to keep our border open to receive our Syrian brothers who are escaping these harsh realities in Syria is still very much in place," Judeh said.
Jordan and U.N. agencies say some Syrian refugees are being shot at as they flee with many having to be treated in hospital on arrival.
"Many of the people coming overnight are injured with wounds and having suffered gunfire and bombardment," Judeh said.
What began as a mostly peaceful protest movement against Assad's family rule has since killed more than 60,000 people, devastated the economy and left 2.5 million people hungry. (Reporting by Suleiman Al-Khalidi; Editing by Myra MacDonald)