According to the report in SETimes, the minister announced, "I'm tired and this is a sufficient reason to quit." It's a less than convincing line - especially given that President Bush is on his way to Albania in a few weeks - and inevitably there has been much speculation about conflicts within the government.
Coming on top of recent dissent within the ruling coalition following the municipal elections, and disputes over the nomination of candidates for President, it does seem that the government is not exactly at peace with itself.
The opposition has been making much of Mustafaj's decision, claiming that it demonstrates the weakness, failure and disunity of the government. Though the opposition can hardly claim to be a shining example of unity either.
The opposition was also protesting about the decision of the Central Election Commission to rerun municipality elections in Elbasan. Though the result from only one district was declared invalid, the CEC decided to repeat the vote in all 21 districts. (The CEC website lists results for 22 districts in Elbasan - I'm not sure why there is a discrepancy in the number.)