Hammond arrived in Mali to visit British forces deployed to help Malian forces ensure territorial integrity from threats by foreign rebels and al-Qaida fighters.
Nomadic fighters and al-Qaida militants took control over parts of Mali after a 2012 coup. The Malian government asked for international military support in January.
Hammond said he was impressed with what British forces were able to do in Mali.
"We are increasing investment in longer-term conflict prevention," he said in a statement.
British forces arrived in March to help train Malian forces. They're scheduled to leave the country, along with Irish troops, near the end of June.
The British military deployed an air force Sentinel surveillance team to Mali to provide information to French and African forces fighting Islamic fighters.
The European and French governments hosted a donors' conference for Mali last week, generating billions of dollars in international aid commitments. Malian leaders at the conference committed to having elections in July.