PESHAWAR, Pakistan (AFP) - A suicide bomber blew himself up as he tried to run into a house owned by a member of Pakistan's ruling coalition Thursday, killing four people but missing the politician, officials said.

The bombing in the troubled northwestern town of Charsadda highlighted the security challenges facing Pakistan's new civilian government in the wake of the bombing of the Islamabad Marriott Hotel last month.

It happened as Asfandyar Wali Khan, head of the Awami National Party (ANP), was visiting a guest in a room attached to his house during celebrations for the Muslim festival of Eid al-Fitr, police and party officials said.

Provincial police chief Malik Naveed told AFP that guards shot the bomber before he blew himself up.

"The suicide bomber tried to pass from the security scanner avoiding a physical search. Two security guards grabbed him but he tried to get away," Naveed said.

"Then he was shot and as soon as he fell on the ground he blew himself up.".

He added: "We had made strict security arrangements and that is why the attacker could not cause more damage or casualties."

A senior party member said that one of Khan's armed guards was killed in the latest attack.

"The incident happened outside the hujra (guest house). One suicide bomber was trying to enter, he was stopped but the bomber blasted himself. The guard was killed," the party member, Haji Adeel, told Dawn television.

Police said the other victims included a policeman and a bank manager who was visiting to pay his respects to Khan.

The ANP is a secular party supporting the rights of ethnic Pashtuns and Taliban militants have carried out several attacks on its political rallies and its leaders.

Twenty-five people were killed in a bombing at an ANP rally in Charsadda in February.

The party joined Pakistan's coalition government, which is led by slain former premier Benazir Bhutto's Pakistan People's Party, after beating allies of former president Pervez Musharraf in elections in February.

Khan is also the chairman of the Pakistani parliament's foreign relations committee.

President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani condemned the blast, the official Associated Press of Pakistan reported.

"Elements bent upon destroying the peace of the country will not be allowed to succeed in their ulterior motives," Zardari, Bhutto's widower, was quoted as saying.

Charsadda has suffered a number of deadly bombings in recent months.

A suicide bomber struck at the mosque of former interior minister Aftab Sherpao in Charsadda on the Eid al-Adha festival on December 21, killing 56 people.

Another bombing in Charsadda in April 2007 wounded Sherpao and killed 28 people.