KARACHI (Reuters) - Pakistans foreign exchange reserves rose to $16.63 billion in the week ending on Sept. 17, from $16.07b the previous week, the State Bank of Pakistan (SBP) said on Thursday. Reserves held by the State Bank of Pakistan rose to $12.79 billion from $12.34 billion, while those held by commercial banks also rose to $3.84 billion from $3.73 billion, said Syed Wasimuddin, chief spokesman of the SBP. The State Bank of Pakistans reserves includes $451 million received from the IMF (International Monetary Fund), said Wasimuddin. The IMF sent Pakistan $451 million and said in a statement last week that the money will go toward Pakistans budget to help with additional spending brought about by the floods and immediate foreign exchange needs. This was separate from the $11b IMF programme. In May, Pakistan received $1.13 billion, the fifth tranche of an $11b IMF loan. The status of the release of the sixth tranche of an $11 billion bailout loan is unclear. It has been delayed until at least November Pakistans forex reserves rose to a record high of $16.77 billion in the week ending on July 2 thanks to foreign inflows worth $750 million received that week. The previous record high was $16.45 billion in October 2007.