Tensions between Palestinian Authority (search) police and military groups erupted into violence Friday as Palestinian gunmen opened fire at a police station, sparking a gunfight that left three people wounded.

It was the second serious clash between Palestinian authorities and armed groups this week, underscoring the delicate task that Palestinian leader Mahmoud Abbas (search) faces as he tries to rein in militants and restore law and order in the West Bank (search).

Abbas has been trying to persuade armed men to lay down their weapons while resisting calls from Israel and the international community for a crackdown. Pressure has increased on the Palestinian leader to take tougher action since a Palestinian bomber from the West Bank killed five Israelis in Tel Aviv last weekend.

The gunmen belonged to al Awda, a small militant group affiliated with Abbas' ruling Fatah (search) party. Representatives of the group said they acted in response to police attempts to arrest one of their members who was driving a stolen car. But a police spokesman said the group was upset that one of its members had been beaten while in police custody.

Witnesses said at least 13 gunmen took up positions outside the police station on Friday afternoon and began shooting, prompting police to return fire. Hospital officials said three people were wounded in the clash, one seriously.

"I heard loud noises and gunfire," said Mohammed Zohel. "I thought the Israelis had gone into the police station, but later I saw it was gunmen fighting the police. It is a real war and very frightening."

Abbas tried to play down Friday's incident, saying Israel's continued presence in Palestinian population centers has hindered his ability to take action. Israel agreed at a Mideast summit last month to pull out of five West Bank towns, but the handover was frozen after last week's suicide bombing.

"We hope that Israeli will withdraw soon from these cities so that we can control security in these cities," Abbas said outside his home in Ramallah. "As long as the Israeli army is in the Palestinian West Bank, there will be breeches and we will deal with it."

Earlier this week, tensions between the Palestinian Authority and the Al Aqsa Martyrs' Brigades (search), a larger militant group linked with Fatah, sparked a confrontation in the nearby town of Jenin.

Zakariye Zubeydi, a militant who is seen by residents as the ruler of Jenin, was irate that the Palestinian interior minister had come to the town without his permission and opened fire on a building where he was holding meetings.

Interior Minister Nasser Yousef ordered Zubeydi arrested, but quickly backed down.

Meanwhile, an explosion rocked the Rafah refugee camp in the southern Gaza Strip (search) on Friday, wounding three people, including two 14-year-old boys and a 6-month-old baby, witnesses said.

There were no details on the cause of the explosion. The Israeli army said it had no information on the incident.

Rafah, located along the Egyptian border, has been a frequent flashpoint of fighting between Israeli troops and Palestinian militants.

But Gaza has been largely quiet since Abbas deployed thousands of police throughout the area several weeks ago.