At least two people are killed in a bomb blast in Karachi.
The bomb appears to have been planted on a motorbike.
It is not clear who or what was the target.
At least 50 people were wounded in the attack.
Two of the injured are in critical condition.
A grief stricken man awaits news of his son.
(SOUNDBITE) (Urdu) MOHAMMAD AZAM, WHOSE SON IS INJURED IN THE BLAST, SAYING:
"My son is inside. Someone please tell me, is this right? Giving misery to someone without reason? Go kill people who are bothering you. Why are you killing innocent people, "
In a separate attack gunmen ambushed and killed six female aid workers and a male doctor near the Capital.
Their vehicle was riddled with bullets
The husband of one of the aid workers says his three year old son was taken out of the vehicle before the women were shot dead
The charity they worked for said they suspected the attacks were linked to recent murders of polio vaccination workers.
Aid workers are frequently kidnapped or killed in Pakistan -- a nation struggling to contain a Taliban insurgency.
Violence rages in Pakistan (1:18)
Jan. 1 - At least two are killed by bomb in Karachi on the same day gunmen ambush and shoot dead six aid workers and a male doctor near Islamabad. Deborah Lutterbeck reports. ( Transcript )