JAKARTA, Indonesia (AP) _ After a coordinated series of bombings outside churches on Christmas Eve killed at least 15 people, Indonesia's president accused his opponents Monday of trying to whip up religious hatred in the mainly Muslim nation.

Christmas day, some churches were only half full as many stayed away fearing new attacks, and police searched worshippers' bags as they entered for services Monday.

The explosions went off Sunday night just before services outside churches in Jakarta and seven other cities and towns. The blasts _ many from parked cars _ went off within minutes of each other, police said.

At least 15 people were killed and 47 others injured, said National Police Chief Gen. Suroyo Bimantoro. Police also found 18 unexploded devices and defused 11, he said. Some had been sent to clergymen wrapped as gifts. One of the bombs, in a parked car, went off outside Jakarta's Roman Catholic cathedral, near the presidential palace and the capital's main mosque.

No one claimed responsiblity for the attacks, which coincided with the final days of Ramadan, the Muslim holy month. There were fears that outraged Christians might retaliate against Muslims at the start of the feast of Eid al-Fitr on Tuesday night.

President Abdurrahman Wahid, a respected Muslim leader, called for calm and asked Christians not to be provoked by forces intent on ``destabilizing the government and creating fear and panic so that the government can not work.''

``There is an effort to use the name of Islam to destroy Christians or to use the name of Christianity to destroy Muslims,'' Wahid said before leaving Jakarta on a visit to the remote Irian Jaya province.

In the past Wahid has accused supporters of ex-dictator Suharto of using violence to create political uncertainty.

``This is the last breath of those who fear that if the government can remain stable we will enter a new era, an era of economic awakening and democracy,'' he said of Sunday's bombings.

The attacks added to a long list of crises and that have worsened during Wahid's 14-month rule, which ended years of authoritarianism. Parts of the sprawling archipelago nation are wracked by separatist and religious violence.

``Even if we know who is behind the bombings, I urge all Christians to forgive,'' Indonesia's Catholic Cardinal Julius Darmaatmadja said Monday.

Most of Indonesia's religious violence has been in the Moluccan islands, where about 5,000 Christians and Muslims have been killed over the past two years.

However, Muslim vigilante groups that have mushroomed in recent months have attacked restaurants and nightclubs in Jakarta and elsewhere, and sectarian fighting has flared in other places.

Five Catholic and Protestant churches were targeted Sunday in Jakarta, where three people were killed. The bombs exploded within an area with a one-mile radius.

A car outside one church exploded in smoke and flames, shattering car windows nearby and causing panic, according to an Associated Press Television News cameraman who saw the blast.

The cameraman, Alex Ginting, was later detained for more than 12 hours along with other witnesses and suspects. He was released Monday morning.

The explosion near the Roman Catholic cathedral left worshippers shaken.

``I am very worried that there will be religious fighting everywhere,'' said Winarno, who like many Indonesians goes by only one name.

An unexploded bomb was also discovered near the cathedral as hundreds of Christians were arriving for midnight Mass and thousands of Muslims were leaving the nearby mosque after Islamic evening prayers.

Four of the dead on Sunday were police officers who had tried to disarm a bomb in Pekanbaru on Sumatra island, the official Antara news agency said.

Antara reported blasts outside of churches in Medan on Sumatra island, where police later found nine unexploded bombs.

Explosions also rocked churches in Bandung and Mojokerto on Java, Indonesia's main island; on Batam island not far from Singapore; and in Mataram on the tourist island of Lombok.

Less than 10 percent of Indonesia's 210 million people are Christians. Many are from the ethnic Chinese minority, which has been targeted by Muslim groups during past civil unrest.

Sunday's bombings in Jakarta were the latest in a series to rock the capital. In September, a car bomb and fire killed 15 people in a parking lot at Jakarta's Stock Exchange. In August, a car bomb blast outside the Philippine ambassador's home killed two people. No one has been charged in those attacks.